Clipping the canvas with the path

Hi
I created a button template which renders a triangle button. The template contains a number of path items placed within the canvas. When the user clicks the button, an animation is started which, beside other things, rotates one of the paths. The problem is that when the path is rotated parts of it look over the bounds of the button. Setting the ClipToBound="true" on a canvas does not help since the button is a triange and the canvas is not. My question is: How can I set the Canvas.Clip property to a Path which defines the outer border of my button? - something like:

<Canvas>
   <Canvas.Clip>
      <Path Width="30" Height="30" Data="..." />
   </Canvas.Clip>
</Canvas>

Any idea will be appreciated.

Uros

Tags: C# (C# 4.0), WPF