How about creating ActiveX control?

To create buttons based on some picture, create a picture in any image editor. Fill the parts that have to be "transparent" in any color which is different from all the others (i.e. magenta, light gray, white).

Now create ActiveX Control project. Set controls' BackStyle property to Transparent. In Picture and MaskPicture properties load the picture you've previously created. Finally, set the MaskColor property to the color that should be transparent (look up).

Basically that's it, but you'll have to add some code though