I'm trying to map Behringer XR18 USB mixer to Sonar Artist tracks. Only mixer channels 1L 2R (plus stereo of those tracks) show up  as ASIO choices for the mixer -should show all 18 tracks to map. Mixer set to send 18 tracks via USB. All firmware and software updated, etc. Anyone seen this issue?

I wait with anticipation for your answer, as I have been looking at buying an XR18 for remote recording gigs.  Interested to see if you get this sorted.  Please keep us informed.

I would immediately contact Behringer. It should work. But they have never had a good reputation for drivers in the past. So a lot of us are sitting this out to wait and see what happens. The units are very appealing to me as well, but I've never had good luck with their gear in the past so I will see what happens.. please do keep us posted on what the company say's and if it does end up working on a PC. I think it works on a Mac. 

OK, here's what I think you need to do.  If you haven't already, download and install the X AIR Edit application for Windows.  Run the app and click on the "Setup" icon at the top-right.  Now click on the "Mixer" tab of the setup page, and look for "USB Interface".  There is a radio button for 18/18 ch or 2/2 ch.  My guess is that you need to select 18/18 for all I/Os to be available.  I would guess that the 2/2 option is just for recording the main stereo bus of the XR18.
 
Try it out and let us know how you get on.  I just downloaded the app to see if I could figure this out for you.  I don't actually have the XR18 yet - saving my pennies.  Good luck.
 
Bill.

I have the Behringer 12 channel mixer with internal recording and it works with sonar platinum perfectly. I love it!

Pfossi~ I already checked that and it is set to USB 18x18. Other than this issue, I have been using the XR18 for 3 months and it has worked very well.

Previous reply should have been to BRuys. Thanks and I'll post outcome when I get there.

Might be good idea to drink some caffeine and edit the subject title :)

Found it. Even though I thought Sonar was set to ASIO, it was set to MME. 
In Artist, go to EDIT/PREFERENCES/AUDIO/Playback / Recording/ Audio Mode and set mode to ASIO.
Looking good. Thanks for the support.