You could use the insert points on the mixer to send to line inputs of the Profire. You insert a TRS cable halfway so it only sends signal and doesn't return it.
So: TRS cable to insert of channel-->line input on profire, that should work I don't know why it wouldn't
EDIT: I just looked at a high res pic of the mixer and only 2 of the channels have insert points. There are 4 sends from the mixer however. You could use the insert point trick on the first two channels, then you could send one channel to the left main output (just pan the channel 100% left), one channel to the right main output (pan 100% right), one channel to the fx send, and one channel to the MONS send. Then you would have 6 total extra channels. That's really ghetto rigged, but if you only need 6 channels it should do you ok for now.