For some unknown reason Microsoft saw fit to make audio in RDP Sessions unidirectional by default. This impacts remote Lync testing. However, there is a way to overcome this limitation, at least when the remote machine is sitting on a Hyper-V host.
First make sure that your RDP client has Local Resources / Remote Audio set to have both Remote audio playback and Remote audio recording as Play/Record from this computer.
On the remote Windows 7/8 computer, open Registry Editor and change the fDisableAudioCapture setting under \\HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp to 0 (zero).
Now we can fully utilize audio in the remote Lync session,
If you generate an Online Meeting Request in Outlook, you will find that all numbers assigned for your Conference Region will be populated in the invite. However, if you generate the request via the Lync 2010 client’s Invite By Email, you are limited to the first three numbers. This has been confirmed by PSS.