mixing objective c code with box2d cocos2d

I am newbie in box2d cocos2d for iOS, but comfortable with objective c. I am currently trying to create a aquarium using objective c and little bit of box2d cocos2d codes. My plan is to create the background and store(a screen from where fishes, aquatic plants and food is buy) using objective C. while box2d will provide me the fishes motion effect. Its a IPad app.

Now, by studying box2d sample code (provided by xcode) suggest that CCDirectorIOS is kind of UIViewController that provides a screen into which box2d physics work.cool…

According to plan, i want to control the aquarium wholly by objective c only fish movement will use box2d physic. So for that, i think we must use objective C UINavigationController whose rootviewController will be a UIViewController(which contains the background of aquarium). then over this , transparent Box2d CCDirectorIOS(which is a type of UIViewController) will be pushed and over this again a StoreViewController(UIViewController for store) will be pushed whenever we want to buy new fish. After buying the fishes, storeViewController will be popped and the Box2d CCDirectorIOS screen(UiViewController) will be refreshed for including the newly bought fish.

is this possible?? if not…show me the right way to do this… Its urgent, so i need to do this maximum by objective C codes.