I'm new here and obviously not a native speaker, so prepare for some "experimental english"

I have a Motu Setup with two 2408 MKIII and a 424 card, that I use for live recordings. But I thought about to use this rig to do some studio work in the future. So I looked deeper into CueMix for perparing headphonemixes. Everything works fine, but I have a question about the routing. I tried the "search", but couldn't find an answer.
"Is there any way in CueMix to route back the stereo mix of an audio sequenzer (Cubase 5)???
When doing overdubs I need to route the recorded basic tracks into the headphone mix but I have no idea how to do that in CueMix? I don't have a mixing desk...just a computer and CueMix.
Cheers
WW