HighlightBrushKey settings not working in Windows 7 - wpf

Question

I have the following style defined in my Resource Dictionary:
<!-- ListViewItem Styles-->
<LinearGradientBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" StartPoint="0,0" EndPoint="0,1">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#F7D073" Offset="0"/>
<GradientStop Color="#F1A62F" Offset="1"/>
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
<LinearGradientBrush x:Key="{x:Static SystemColors.ControlBrushKey}" StartPoint="0,0" EndPoint="0,1">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#F7D073" Offset="0"/>
<GradientStop Color="#F1A62F" Offset="1"/>
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
<LinearGradientBrush x:Key="MouseOverBrush" StartPoint="0,0" EndPoint="0,1">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#E4F0FD" Offset="0"/>
<GradientStop Color="#D7EAFD" Offset="1"/>
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
<Style TargetType="{x:Type ListViewItem}">
<Setter Property="Foreground" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataForeground, Converter={StaticResource ColorToBrushConverter}}" />
<Setter Property="Padding" Value="1,0,1,0" />
<Setter Property="FontWeight" Value="Normal" />
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="BorderBrush" Value="Transparent"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter Property="Background" Value="{StaticResource MouseOverBrush}" />
<Setter Property="BorderBrush" Value="#C6E1FC" />
<Setter Property="BorderThickness" Value="1" />
</Trigger>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Foreground" Value="Black" />
<Setter Property="BorderBrush" Value="#909090" />
<Setter Property="BorderThickness" Value="1" />
</Trigger>
</Style.Triggers>
<Style.Resources>
<Style TargetType="Border">
<Setter Property="CornerRadius" Value="2"/>
</Style>
</Style.Resources>
</Style>
<!-- /ListViewItem Styles-->
When i was using windows XP the behavior that I was getting was my gradients were used for the Hightlight and the selection. Now i have switched over to using Windows 7 and it seems like the gradients are no longer used the highlight/selection colors are now the light blue of the VS look.
Any suggestions on why this would be happening and how do I fix this in such a way that it works the same on Windows XP and Windows 7 (we have a multiplatform environment)
Thank you.
Full Solution after comments
<LinearGradientBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" StartPoint="0,0" EndPoint="0,1">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#F7D073" Offset="0"/>
<GradientStop Color="#F1A62F" Offset="1"/>
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
<LinearGradientBrush x:Key="{x:Static SystemColors.ControlBrushKey}" StartPoint="0,0" EndPoint="0,1">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#F7D073" Offset="0"/>
<GradientStop Color="#F1A62F" Offset="1"/>
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
<LinearGradientBrush x:Key="MouseOverBrush" StartPoint="0,0" EndPoint="0,1">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#E4F0FD" Offset="0"/>
<GradientStop Color="#D7EAFD" Offset="1"/>
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
<Style TargetType="{x:Type ListViewItem}">
<Setter Property="Foreground" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataForeground, Converter={StaticResource ColorToBrushConverter}}" />
<Setter Property="Padding" Value="1,0,1,0" />
<Setter Property="FontWeight" Value="Normal" />
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="BorderBrush" Value="Transparent"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter Property="Background" Value="{StaticResource MouseOverBrush}" />
<Setter Property="BorderBrush" Value="#C6E1FC" />
<Setter Property="BorderThickness" Value="1" />
</Trigger>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
<Setter Property="Foreground" Value="Black" />
<Setter Property="BorderBrush" Value="#909090" />
<Setter Property="BorderThickness" Value="1" />
</Trigger>
<!-- This part of the triger is for when Windows Aero theme is turned on Win Vista/7-->
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListViewItem}, Path=IsSelected}" Value="True" />
<Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListView}, Path=IsKeyboardFocusWithin}" Value="True" />
</MultiDataTrigger.Conditions>
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
<Setter Property="Foreground" Value="Black" />
<Setter Property="BorderBrush" Value="#909090" />
<Setter Property="BorderThickness" Value="1" />
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListViewItem}, Path=IsSelected}" Value="True" />
<Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListView}, Path=IsKeyboardFocusWithin}" Value="False" />
</MultiDataTrigger.Conditions>
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
<Setter Property="Foreground" Value="Black" />
<Setter Property="BorderBrush" Value="#909090" />
<Setter Property="BorderThickness" Value="1" />
</MultiDataTrigger>
</Style.Triggers>
<Style.Resources>
<Style TargetType="Border">
<Setter Property="CornerRadius" Value="2"/>
</Style>
</Style.Resources>
</Style>

Answer 1

The default Style on Aero is a bit different then the Luna themes. In Aero, there is a trigger like so in the default Style:
<Trigger Property="IsSelected" Value="true">
<Setter Property="Background" Value="{StaticResource ListItemSelectedFill}"/>
<!-- ... -->
</Trigger>
While on Luna, it looks like:
<Trigger Property="IsSelected" Value="true">
<Setter TargetName="Bd" Property="Background"
Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
<!-- ... -->
</Trigger>
So you can see the default Style for Aero, doesn't use the HighlightBrushKey at all. This is mostly because those brushes are based on a single solid color. But the Aero theme has a lot of gradients, which can't be represented by the old style colors.
You would need to set the Background property as well to apply it on Aero, like so:
<Trigger Property="IsSelected" Value="true">
<Setter Property="Background"
Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
<!-- ... -->
</Trigger>