WPF Visual States & changing colors - wpf

Question

My WPF application needs to have two different color schemes based upon time of day, a day-mode and a night-mode. I'm trying to modify the template used by a third-party WPF control so it will work with the different color schemes.
The control in question uses visual states to define the transition from selected to unselected:
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Calendar:CalendarButton}">
<Grid x:Name="LayoutRoot" Background="Transparent">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="SelectionStates">
<VisualState x:Name="Unselected"/>
<VisualState x:Name="Selected"/>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}"/>
<Chromes:ButtonChrome x:Name="SelectionChrome" CornerRadius="1" Margin="2" RenderNormal="False" RenderSelected="{TemplateBinding IsSelected}" RenderFocused="{TemplateBinding IsFocused}" RenderHighlighted="{TemplateBinding IsMouseOver}" />
<Border x:Name="TodayVisual" BorderThickness="1" CornerRadius="2" Margin="1" Visibility="Collapsed">
<Border.BorderBrush>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FF282828"/>
<GradientStop Color="#FF5F5F5F" Offset="1"/>
</LinearGradientBrush>
</Border.BorderBrush>
</Border>
<ContentPresenter x:Name="Content" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
I need to change the Background, BorderBrush, and Foreground properties of the ButtonChrome control when the visual state is "Selected". How do I do this?

Answer 1

I have found that on most controls that have a Chrome elements (whether they be Microsoft or other parties controls), it is necessary to remove the chrome element, and re-construct it by hand as they often do not provide a method to change them (i.e. no way to substitute a template).
However, if anyone else has a better way, I am all ears.