BBM video chat with grandfathered Unlimited AT&T

Is it true that in order for the BBM video chat to works with other Z10 users, one must NOT be in grandfathered unlimited plan? Or is it more like software issue which they will fix on 10.1 OS? (like how Iphone first release, their facetime can only be through wifi).

I would really love to have bbm video chat without looking for wifi hot spot and use their 4G.

Thanks

Posted via CB10