I think you guys are talking about two different issues here.

1. ALmost every keyboard will sync to a drum machine, but in that case just the midi tempo will get synched and the patterns will come from the drum computer.
Disadvantage: its hard to synch fills, intros etc with your arranger, they would have to play a fill in they same lenght and time.

2. Option is to just use the sounds out of a rack module or drum machine but let the arranger play the pattern. This solves the issue above. BUT, indeed I dont think that yamaha transmits the actual midi notes for the drumtrack to its midi-out port.