Interface - starting up

[Fyxe]

Hey folks

I've decided to make my own UI with my own skin & graphics, but!. Last time I tried, I couldn't make backgrounds invisble, with KG panels, so there is, forexample, some holes in the panels, that shows the wow screen. Kinda hard to explain , that there's some of the panel that is simply invisible, How do I do that?
any special color I shall use?. I have acces to Photoshop CS4