Disable Incoming SMS sound when on Phone Call while sound profile is set to vibrate

[yettie10ff]

I have a TP2 and no matter what ROM i'm using I always have the following problem.

My phone is set to vibrate, however when I am in the middle of a phone call and a text message comes in, I hear an annoying alert sound that rings to notify me that I have an incoming sms. It always interrupts my conversation and I can't hear the other person and I imagine they hear the weird noise on their end.

Does anyone know how to disable this incoming sms sound? I would think that having the phone set to vibrate would do it, but alas it does not do the trick.

Would love to turn that off!