I'm assuming by the above that you have been able to connect your BT head phones to the old iPad & the iPhone - correct?
Well, the process should be the same on the iPad2 - I have some BT headphones that work fine w/ my iPad2 (iOS5) - did you put your phones into 'pairing' mode and then have the two devices try to discover each other? I'm assuming that you did but just saying -
If not already done, you might want to 'Restart' or 'Reset' (if the other is unsuccessful) the iPad2 - Directions HERE - good luck and please post back if not helpful - I'm sure others will jump in w/ suggestions!