gswitz
Since you have joined the RME club, be sure to install DigiCheck as well. You will find it on the RME-audio.de downloads page. It is awesome software that comes with your device. I don't usually run sonar without running at least one window of DigiCheck and sometimes I run a heap of them.

If you are doing something live and mixing in the RME TotalMix software, you can make the recording with DigiCheck and never launch sonar until after the gig. Works like a charm. You can even record synths you play in sonar using the loopback feature.

DigiCheck is really made for live stuff. It doesn't 'dropout' ever. It just keeps going. You will never look up half way through a gig a see it isn't recording, unless you didn't ever start it. ;-)