Pry off the SS edge trim and you'll find a 'track' for the SS trim is pop riveted thru the aluminum inner door panel to the door frame. As Craig said, the upper hinge must be removed to totally remove the panel.
Drill out all the pop rivets and off it comes.
The SS door trim can be resused as long as it isn't bent while trying to remove it. Gently start at one of the corners and use a flat wide screwdriver to lift it up. If you don't plan to reuse it, grab it with vise-grips and snatch it off.
We removed the SS trim and upholstered a panel that fits the footprint of the aluminum panel. Quiet and much warmer in sub-freezing weather.
Zero huh? Couldn't deal with that...
We got something like 14* low tonight...hate it. HOWEVER, as is typical here in NC, this weekend will see 60s again! Very nice!
BTW, the upper hinge bolts are prone to seizing. Use some anti-seize compound on the bolts when replacing them. Be careful with the adjustment too. Precisely mark the upper hinge location. It is critical to alignment of the door. Don't slam the door shut when bolted back on unless you have a window open. You may find yourself jammed out of the bus. This is true if your adding a CG lock too. Leave some way to get into the bus until your satisfied that the lock or door is working correctly.