Last year I tried to make sound work on this card but I couldn' t.
I finished buying a small usb sound card to capture and mix the audio
and video in the system.
Although Viewcast company says Linux is supported, its not and they
don't give any support about it.
Somewhere I read using Red Hat sound on Osprey 230 works but I never tried.
Please if you do it, let me know.
Not sure if that helps you much but it appears you'll have to get a different audio capture and mix them.
I can't confirm how accurate the above statement is regarding Red Hat support but found this statement on the ViewCast website.
For select Osprey® PCI™ and PCI-X™ cards, Linux support is available from the Linux Open Source community. Modern Linux kernels include a module that supports the chipset on the PCI/PCI-X capture cards. Please note: these drivers are supported by the Linux community and not by ViewCast.