Premium Flush Side Mount Control Trim Control

I have a 2000 year Yamaha flush mount control that looks like the 6X0-48206-12-00. The trim button intermittently works although the bow and motor trim works repeatably. I was able to take the handle off of the stationary mount but can not find any other way to disassemble to hold the switch in hand. I received a repair part from local Yamaha dealer as P/N 704-82563-50-00 which is only the switch and cable.
A) How do I disassemble down to the switch
B) Is there another P/N that has the switch and handle as an assembly?

Thanks much,

[boats.net]

Look at this diagram, remove number 54(neutral lock) to get access to number 50 screw that holds handle in place OUTBOARD RIGGING GUIDE CONTROL SIDE FLUSH PREMIUM Diagram