Yes, Sonar can export loops.
I always thought it could, and perhaps even used it once or twice. But it took a couple of tries before I found out how-to.
1. In sonar find the audio clip you want to make into a loop. Cut it out in the lenght you like etc.
2. Double click on the audio clip.
3. Now you have the loop editor.
4. If you haven't made it loop already (using right mouse button), then do it now pressing the button no. 2 from left in the upper left corner.
5. Did you notice what button no. 1 in that upper left corner was? YES, it is the save button. Press it and save your loop.
Now, you can use it just as any other loop on your disk.