After scanning the thread I'm going to toss out a general troubleshooting tip I've learned about "disappearing" audio devices. It may help and it may not.
 
Simple version: Make sure the audio interface's "power" is turned ON and the USB cable is connected BEFORE launching SONAR.
 
In my experience if connected and properly installed Audio and MIDI devices are not appearing in the appropriate SONAR devices areas it is usually because I did not give Windows and the device drivers enough time to fully load before opening SONAR. Because of this SONAR doesn't see the devices when it first opens and thus the devices aren't on the list(s). If I close SONAR, wait a while (or reboot), check my connections and whatnot the devices will appear as expected.
 
So...
 
1) Boot up and wait a minute
 
2) Connect/power up your audio/MIDI devices and wait a minute
 
3) Open SONAR and if you allowed enough time for your devices to get their shiz sorted out then everything should be available
 
 
Also... another rule of thumb I follow is to ALWAYS use the same USB port on your computer that you installed a device on. So let's say you have 3 USB ports on your system. You fully install your audio interface on USB port 1. ALWAYS plug your interface into that port from now on. If you install a MIDI keyboard on USB port 2 always use port 2 for that device... and so on.
 
It MAY not cause problems if you don't and at this point it may not be relevant but since I've adopted both of these habits I NEVER seem to lose my devices in the SONAR Prefs.
 
Hopefully that shakes something loose.
 
Cheers.