Hi all, I am sure this question has already been answered, but if so, I couldn't find it in the forums or on the web, so I'm posing it here.  How precisely does one enable loopback functionality in Totalmix with a Fireface 800?  From the manual (SS 33.5), I'm supposed to be able to hold down control and click on the white button on the output row (e.g. "AN 1") and it's supposed to turn red.  That doesn't work for me.  I can get it to turn yellow, but not red, no matter what other keys I hold down, to include open apple, alt, and fn.  What am I missing?  I'm using the Fireface Mixer software version 2.64 on Snow Leopard.

Thanks
John