I've seen other software with this before. Basically when u are selecting ins and outs, you can coose which sound card/audio device u want to use.
This would mean u could use ur third party (pro) audio device for music, and ur internal sound for pre cueing.
peace
Dual Sound Card Support, PRE CUE SAMPLES
with a multiple out ASIO soundcard, you can assing whatever channels you want for the stereo pre-listen in Lives preferences>audio>pre-listen. If you have that out going to headphones, you can monitor the pre-listen stuff in live (metronome, tracks active and armed to record (but NOT with monitoring activated)) on the headphones, and send the rest of it out through the master. It would seem redundant to have an internal AND external option as far a monitoring and pre-listening goes--if you have a multi-out ASIO soundcard, you should be good to go.