Hi is there any way to restoring an iPhone thats not detected?

Basically I have an iPhone 4 that will not charge, will not be detected in iTunes, however whe the phone is turned off it turns back on when plugged in. I was going to go to the apple store but it is using iOS 5 beta, which I bought a slot on a developers account. I'm guessing if I went into the genius bar they would see iOS 5 installed and it will magically not be covered by warrenty am I right about this? Also if I am, is there a way to restore the iPhone back to the normal firmware (I know this is possible due to apple still distributing and I did it the other day for someone elses) Basically, is there any way for itunes to detect, the mac has no clue that I have plugged it in though, and neither does windows.