Door panels on a WC

I have to change the guts on the doors from a WC 27 ambulance to a WC pick-up. Glass and door latch and handles. Stupid question follows, how do I get the door latch handle and the window crank off so I can get the door panel off?? The panel is off the WC and it looks like a roll pin held the handles on but what ever is holding the handles on the ambulance doors is hidden by a little trim ring between the handle and the panel. I don't want to do what I normally do in this case, break something. Any help will be appreciated.

i believe that trim ring, pushes back, and exposes the pin, or clip. i use a large pair of plyers(tips wrapped n tape) slip over the handle(going toward the door), and push into the door,(may be spring loaded) then the pin/clip will be exposses, your local auto store sells a tool like these... they are handy, a screw driver works just as well to pop the clip out.. once you ve depressed the trim ring.

Amazon.com: 7 pc CAR DOOR PANEL, TRIM & Windshield REMOVAL TOOL: Automotive

thanks, I'll give it a shot