RDP MaxBandwidth key

Hello

We use some sort of dictation software ,users are logged into the terminal server at the remote sites when they listen audio and when it is  choppy and jittery we would edit /alter the MaxBandwidth value for your RDP connection by changing this registry key: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32\Terminal Server\RDP MaxBandwidth: 0x000056b9 (22201)

This was working well in 2003 but since moved to  2008 R2 we were not able to find mentioned registry setting and to alter audio quality.

Does anybody know if there is similar key in W2K8 R2 registry?

We already tried with audioqualitymode entries but this did not give desirable results as mentioned registry settings 

Thank you