Yeh i'd also like to know how to split them, im using FL... i do it that way: i send my synth (or whatever i want to split) to insert 1, route the signal from insert 1 to inserts 2,3,4 and buss them together in insert 5. now you can control hi, mid and low seperately (inserts 2,3,4 after EQ or cut)...

http://www.youtube.com/watch?v=zIh5AHxh-Ok
It seems easy but i cant seem to get it just right, so i was wondering if anyone can figure out how to make the high pitch sound that comes at the 1 minute mark