USB Audio/Mixer problem

I recently purchased a Creative Labs Sound Blaster MP3+ which seems to 
work OK under FreeBSD 5.3-BETA.  A couple of exceptions, though.  It 
only seems to understand 48KHz and have to convert 44.1KHz -> 48KHz or 
else the device locks up.  I can live with this.  My concern is that 
when booting verbose or with USB_DEBUG set, when the device attaches, 
it declares that there are 12 mixer devices.  So when I type in mixer 
at the command line, I would expect to see volume, pcm, linein, etc...

But, here's the output of mixer:
Recording source: mic
Mixer pcm      is currently set to  12:12

That's it.  Any ideas to help me get some useful mixer settings?

Thanks!