I bought a Motif XF6 and have been trying to record the song (MIDI) created on the workstation to different channels in Cubase for each voice. My connection is through a USB cable.

Cubase can simply open your Motif XF Song.

Yes, you could setup to record it over in realtime, but Yamaha has "taught" Cubase to read Motif XF ALL data files (.X3A) - it can open it and I,port the Song data to individual tracks of Cubase. This is much easier than setting up a MIDI Track, synchronizing MIDI clocks, doing the transfer, then using Dissolve Parts to split the data to separate tracks.

Please the following article for step-by-step instructions: Cubase: Motif XF Song Import

If you get stuck or have questions, let us know.... Post back here.