Maybe this will answer some of your questions:
http://www.cakewalk.com/support/docs/sysx.asp

Again, as long as the saved sequenserfiles you have from your
KN750 don't have the drums as GM, you have to remap the drums,
and that's something I'm not familiar to.
You can i.e. transfer the tracks from KN to G8 by midiconnection
when your equipment is proper set, but you will not manage to
transfer the drumtrack properly, if transfer at all.

But here is an older posts from the forum where similiar topic
is dicussed, maybe it is for any help:
http://www.synthzone.com/ubbs/Forum25/HTML/000649.html

Cheers
GJ