It seems that after using hactivation push doesn't work on the iphone. But I figured out a way to do that. I wanted to share it with you guys so that some people can be helped until dev team finds another way.

After using a custom restore without activation, I used an old AT&T sim to activate the iphone(it didn't have service). Then I installed ultrasn0w, and tried the push. Everything works perfectly fine after that.