Wait for texture to be loaded before starting game

I support user content (for the background) in my iPhone game and would like to load the content before the game starts. All t$$anonymous$$s is working fine using www.texture. The problem is that on startup the original background (asset texture) is shown for a second until the new texture is loaded (using www.texture with local file).

Any idea how I can keep the game from starting until the user texture is loaded? As far as I can see I must use a coroutine to load the actual texture and at the point where the www request is done the game is running already.

Thanks!