[FLEX2 AS3]Need help getting data objects onto the stage

Hello Everyone! please bare with me as im new to AS3 and flex and i may not know the exact terminology but ill do my best:hugegrin: .

I am building an application in flex builder 2 using AS3 and for some reason I cannot instantiate 2 custom controls that i have made. the first control extends the TileList and the second extends the ComboBox. I was able to get them on the stage if I make my default application a mxml file but when I try to instantiate them with an as file as my default application i get nothing at all(not even an error). From what ive read hear I guess these are Non-DisplayObject classes but I cant figure out how to get them on the stage. Any help would be greatly appreciated.