Voice dialing w/Siri and Jawbone headset - no sound

Hello! Just set up the 4S and paired my Jabone ERA (software is current). When I hold down the call button and ask Siri to "Call my wife" or "call [401-XXX-XXXX]" or "call [some other name in my contact list]" it successfully dials the number I seek. However, when the call connects the ERA's speaker/mic does not transmit or recieve. The "audio source" says "headset", but nothing. When I tap, in audio source (and while call is connected), "iPhone" I callee can be heard and they can hear me. When I tap, again in audio sources, "headest" it works. While this seems like an easy work around, it sure makes it difficult while trying to voice dial while driving or doing anything else handsfree. Help? Thanks!