Vista - Themes and ButtonChrome

Hello,

I was trying to override the default styling of a button in my
application to add additional content inside the button and in my
style there's something like this:

<ControlTemplate TargetType="{x:Type Button}">
<Microsoft_Windows_Themes:ButtonChrome SnapsToDevicePixels="true"
x:Name="Chrome" Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
RenderDefaulted="{TemplateBinding IsDefaulted}"
RenderMouseOver="{TemplateBinding IsMouseOver}"
RenderPressed="{TemplateBinding IsPressed}">
<! -- Content goes here -->
</Microsoft_Windows_Themes:ButtonChrome>
</ControlTemplate>

The problem I have is this: Now when i run my app on Windows XP, the
button doesnt obey the theme but is instead Vista styled all the
time. Is it possible to use ButtonChrome and get it to use the actual
theming.

Thanks in advance,
Martin