Add custom combobox scrollbar style wpf - wpf

Question

I know that I can find this on http://mark-dot-net.blogspot.com/2008/06/styling-listbox-with-silverlight-2-beta_21.html but I would like to be able to just do something like this:
<ComboBox Width="163" Height="30">
<ComboBox.Style>
<Style>
<Setter Property="ScrollViewer" Value="{StaticResource Custom}"/>
</Style>
</ComboBox.Style>
</ComboBox>
But because of the ScrollViewer is not available, I tried doing something like this:
<ComboBox Width="163" Height="30">
<Style>
<Setter Property="ScrollViewer.Style" Value="{StaticResource Custom}"/>
</Style>
</ComboBox>
But it does not work and if I keep in the Combobox.Style it gives me the error Style object is not allowed to affect the Style property of the object to which it applies to. I have also tried doing ScrollViewer.Template but my computer crashes when I do this /: Is there a way to do this without using the method in the link I provided earlier? My style xaml is:
<ControlTemplate x:Key="VerticalScrollBar" TargetType="{x:Type ScrollBar}">
<Grid>
<Grid.RowDefinitions>
<RowDefinition MaxHeight="0"/>
<RowDefinition Height="0.00001*"/>
<RowDefinition MaxHeight="0"/>
</Grid.RowDefinitions>
<Border Grid.RowSpan="3" CornerRadius="2" Background="Transparent" />
<RepeatButton Grid.Row="0" Style="{StaticResource ScrollBarLineButton}" Height="18" Command="ScrollBar.LineUpCommand" Content="M 0 4 L 8 4 L 4 0 Z" />
<Track Name="PART_Track" Grid.Row="1" IsDirectionReversed="true">
<Track.DecreaseRepeatButton>
<RepeatButton Style="{StaticResource ScrollBarPageButton}" Command="ScrollBar.PageUpCommand" />
</Track.DecreaseRepeatButton>
<Track.Thumb>
<Thumb Style="{StaticResource ScrollBarThumb}" Margin="1,0,1,0" Background="#E43D47" BorderBrush="{StaticResource HorizontalNormalBorderBrush}" />
</Track.Thumb>
<Track.IncreaseRepeatButton>
<RepeatButton Style="{StaticResource ScrollBarPageButton}" Command="ScrollBar.PageDownCommand" />
</Track.IncreaseRepeatButton>
</Track>
<RepeatButton Grid.Row="3" Style="{StaticResource ScrollBarLineButton}" Height="18" Command="ScrollBar.LineDownCommand" Content="M 0 0 L 4 4 L 8 0 Z"/>
</Grid>
</ControlTemplate>

Answer 1

Just declare a ScrollViewer style in the ComboBox's Resources block:
<ComboBox ItemsSource="{Binding Items}">
<ComboBox.Resources>
<Style TargetType="ScrollViewer">
<Setter Property="Background" Value="Green" />
<Setter Property="Padding" Value="20" />
</Style>
</ComboBox.Resources>
</ComboBox>