HFP/HSP Telephony profile doesn't work with Bluetooth USB dongle

Greetings,

Using Fedora 18 x86_64, I've tested two different USB Bluetooth dongles 
(cheap generic Cambridge Silicon and more expensive BlueRigger BTD-400) 
and two different headsets (Motorola SF600, BrainyTrade BH-M20), in all 
combinations, the A2DP High-Fidelity profile for audio output works, but 
the HFP/HSP Telephony profile does not.

I contacted BlueRigger about this and they tested for themselves on 
different hardware and got the same result. BlueRigger says the HFP/HSP 
Telephony profile works fine with Ubuntu, which they say doesn't use Bluez.

I don't know if this problem is new in Fedora 18, because I didn't get 
the dongles until after I upgraded from Fedora 17.

I've reported this in Red Hat bugzilla 
<https://bugzilla.redhat.com/show_bug.cgi?id=905283> and emailed the 
Fedora test list 
<http://lists.fedoraproject.org/pipermail/test/2013-February/113598.html> about 
it; there has been no response to either.

Any suggestions or insights into how to resolve this issue would be 
appreciated.

Regards,

Jonathan Kamens