Has anyone figured out a way to add your own icons to the glass buttons in TDD?

Example: They have a "source" button in the glass bitmap library w the satellite dish icon. I want to have a glass button w a Dish Netowrk logo/icon on it instead. I can re-size the Dish Net logo in Photoshop to make it the exact size (94x75) of the original glass button, but when you drag the new logo to the original glass button location, the "glass" features are lost. Ive tried this with the blank buttons as well, like the round glass buttons.

It would seem that I need to do this in "layers", starting with a blank glass button, then adding the icon/logo as a second layer. Does this sound right? Im not a Photoshop guru, so if is the case Ill turn it over to someone who is.

Related question:
Does anyone have a BLANK bitmap of the glass 94x75 button? All I see in the bitmap library are ones that already have icons imbedded in them.