Hi guys, i just cant understand why, i know you cant pair an iphone device bluetooth to a different mobile device, but another iphone?

I have an iphone 4 running ios 5.1.1

and an iphone 4s running ios 6.0.1, does firmware matters?

Why both bluetooth is not discoverable, placed them side-by-side, both turned bluetooth ON, so whats the problem?

And another thing;

I already paired the two with a bluetooth handsfree headset, successfully connected, but i cant listen music from the headset, why is that?

Anyone, please?