Two options:
- add a method to cache CCTexture2D* objects with a key (unique string)
- save the UIImage to disk (in Application Support directory), then load it as normal with cocos2d
The latter option will cause a notable delay due to the save & load process. I'd recommend the first approach. Most of the code you need to write that function is already in CCTextureCache, I believe there may even be just the method you need that only needs to be made public in the interface.