I am able to use VoIP with the SIP client (over WiFi) and my Nokia BH-503 headset at the same time without any issue regarding simultaneously using the WiFi and Bluetooth radios (which are on very similar frequencies admitadely).
The two problems that I do have though:
1) I can't answer an incoming VoIP call on the headset. This seems to be a known bug with the SIP client mentioned here:
Voip with SIP on Nokia E65 and Bluetooth headset - Developer Discussion Boards
2) The person at the other end hears an echo of their voice. I am not sure what is causing this but its definitely not present on a call over the cellular network with the headset and it doesn't happen when I use the Nokia handset itself, only through the headset.
Perhaps there is some echo cancelling on the phone which isn't launched when a call goes through the SIP client, or perhaps there is echo cancelling on the network side somewhere?
Does anyone else have this problem? Has anyone managed to stop it?
Thanks
Simon