I can't seem to print envelopes on the xerox workcentre 7345. I fed the envelope into the bypass tra...

There is a lengthy set up process to that. I would recommend going ot Xerox.com, then at the home page, click on Support and drivers. When you get to that page, type in 7345, then click on the support home page, once there type in envelopes and the step by step instructions are there.
You are correct, setting up envelope printing on that machine can cause you to beat your head against a wall. The machine settings and the driver settings MUST be set exact. And it may take 3 or 4 tries, even for a service rep to get it all correct. Trust me on that LOL.
But once set up, it does a nice job. It is just very picky. Personally, I think it is way over designed just to print an envelope.