Is it possible to override one part of a control template in a Telerik WPF theme?

I am using the Telerik Windows 8 theme in my WPF application.  However, I do not like the way the checkbox checked state is indicated using a colored square rather than an actual checkmark as in the Windows 7 theme.  It was very simple to copy the checkbox template and modify it to use the checkbox checkmark from the Windows 7 theme checkbox template.

However, I am having trouble finding a way to add the style that contains this modified template to my Application.Resources in such a way as to apply it to all checkboxes in my application.  For some reason, the template in the Telerik Windows 8 theme continues to be the one that is applied.

I have tried a few different approaches, yet nothing seems to work.  My latest approach is to add the following style to my Application.Resources resource dictionary:

<Style BasedOn="{StaticResource {telerik:ThemeResourceKey ThemeType=telerik:Windows8Theme, ElementType=CheckBox}}" TargetType="CheckBox" >     <Setter Property="Template">     ....     </Setter> </Style>

Does anyone know the answer to this question? Is what I am trying to do possible?

Thanks, Craig