Thanks for that info. Not only was I able to get that rear panel off, but while I was in there I was able to track down and disconnect the cable/connector for the front USB port.
My problems have found a solution within a couple of hours! Gotta love the internet! ...and a big THANKS to The Hat!
I'm planning to implement a couple of these printers in a post-secondary education lab setting and need to disable, lock or block the USB ports to prevent un-chargable prints. They will be connected to the network and a PaperCut server to recover costs.
How difficult is it to remove the case...