Change the menu highlight color

Hi,

I'm new to the WPF and i created a menu in XAML. Now i need to change the
color the menu items have when they are rolled over. How can i do this?

This is the XAML i have so far:

<Grid x:Name="LayoutRoot">
<Rectangle Stroke="{x:Null}" Margin="22,81,8,0" VerticalAlignment="Top"
Height="19">
<Rectangle.Fill>
<LinearGradientBrush EndPoint="1,0.5" StartPoint="0,0.5">
<GradientStop Color="#FF789BB8" Offset="0"/>
<GradientStop Color="#FF002B5F" Offset="1"/>
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<Menu RenderTransformOrigin="-1.59,0.44" HorizontalAlignment="Left"
Margin="22,81,0,0" VerticalAlignment="Top" Width="261" Height="19"
Background="{x:Null}" Foreground="Red" AllowDrop="False" Opacity="1"
OpacityMask="{x:Null}" ForceCursor="False">
<MenuItem FontSize="11" Foreground="#FFFFFFFF" Header="_Bestand"
OpacityMask="{x:Null}" Margin="0,0,0,0" OverridesDefaultStyle="False" >
<MenuItem Header="Exit"/>
</MenuItem>
<MenuItem Margin="0,0,0,0" Foreground="#FFFFFFFF" Header="Instellingen"/>
<MenuItem Margin="0,0,0,0" Foreground="#FFFFFFFF" Header="Help">
<MenuItem Header="Exit"/>
<MenuItem Header="Exit"/>
<MenuItem Header="Exit"/>
</MenuItem>
</Menu>
</Grid>

Thanks.

Ben