Buttons, picture fill, and shadows

I was trying to use some cool images to create buttons with textures (e.g. with diamond tread plate). However, when I use a picture to fill the button (Format Shape / Fill / Picture or Texture Fill and then select Tile picture as texture, my button loses its shadow.

I can fill buttons with colors and get shadows, and I can get pictures with shadows, but using a picture as the fill on a button, and the shadow... well, it's like it's standing outside in the middle of summer at noon: no shadow at all.

Any ideas on how to get around that?

Thanks.