This is what I have run into and I don't know if there might be a work around.
Fist off, envelopes through the bypass misfeed from print mode, not copy.
If i set up a custom size in drawer 2, 4.13 x 9.5" and thick paper, the machine will run it, but there are two glitches.
One: horrible creases.
Second: even though the template in word is set up to com 10, and the driver, RPCS, is set up to custom size (4.13 x 9.5), when the job reaches the 1232 it sees unmatached paper sizes and you have to force the job through manually.
If anybody has any input, I would greatly appreciate it. Thanks for yout help.