Unity UIKit integration

Hello I'm new to unity but I was using other game engines such as udk , trinigy etc.. However recently I've seen a problem in unity which I'm not able to solve.Maybe you can help me with that Our application is basically a messaging application which uses lots of uikit classes such as tableviews uipickerviews navigationcontrollers, etc.. and when a user presses a button in our application the game window should open(which our recent application can make that with pure opengl) but as far as I understand unity takes control of the whole screen and we are not able to use UKit objects such as navigation controllers. Is there any trick to accomplish that ? I mean I want to use my regular iphone application with navigation controllers,table views etc and when I press a button I want my unity view to open and then when I press a button in unity view I want to navigate back to my UiKit views Is something like that possible? Even if there is a paid package for that if you can give me the adress I can buy it? Thanks