I am being told that the DC main breaker, the FB main breaker and the Engine main breaker (which runs through a start solenoid) is the way all Oceans are wired and that such a method is compliant. Not too sure about that.
If you are sure about the 3 momentary switches, then you probably jump them. You need to know if they are N.O. or N.C. momentary switches. N.O. switches would be jumped in parallel. N.C. switches would have to be jumped in series.
What model genny?