Volume greyed out for USB audio device

I am having trouble with a Lyra Wireless unit which is a USB device that takes over as sound card and transmits the audio wirelessly to a reciever which can be connected to a stereo.

The drivers are automatically loaded correctly, but there is no sound. When I go to Control Panel->Sounds and Audio Devices, in the Volume tab, the Lyra is the default audio device, but the volume is set to low, and all the options in the Volume tab are greyed out. If I change the default device to the onboard audio, I have full access to the Volume tab.

I've attempted contacting Lyra for help (which they can't), and I've tried disabeling the onboard audio devices, but I still cannot gain access to those volume settings. This happens on both my laptop and PC which have XP Pro installed. Any ideas? Thanks

After some further searching last night I found some differences in the Volume registry keys for Intel Integrated Audio and Lyra. Intel had a Master Volume key, while Lyra only had a Speaker key. I attempted to add the Master Volume values to Lyra, but it did not change anything. I do not have that much experience with the registry??????