Microphone issues during SIP calls

Hi all,

I've had this phone for a couple of days and am having issues with the microphone. Volume seems to be okay during GSM/3G calls, but is extremely low - to the point where I am litteraly unhearable to the other party - while on SIP calls. The problem applies to calls using the handset, and while using a bluetooth headset. The only instance where the other party is actually able to hear what I am saying is when using the speakerphone feature.

I've tried numerous SIP clients, including Bria, 3CX, CSipSimple and SipDroid, however, problem still persists. This leads me to think that it's an issue with the Samsung firmware. Anyone else experiencing similar issues? Any place where I can officially report this issue or check if it has already been reported?

Thanks!