Default Help for Bluetooth and SIP calls

Hi to all,
I have a problem with my Samsung Galaxy S III, 16GB, Android 4.3, stock rom, and the integrated SIP voip system (Call Settings < Internet calls settings) with bluetooth headset: when I receive a SIP call the audio is not transferred to the bluetooth, I do not hear anything and the microphone does not transmit. Otherwise, when I make a sip call everything works perfectly. I have tried many SIP providers and many BT headset but this issue remain.
It 'possible that some of you do a test to see if the problem is only mine or if it is a S III bug?
Thank you!