It's not exactly clear what you mean by "putting those escape sequences at
the top". If you mean that the data you are trying to print is preceded by
the escape sequences to configure the printer, I believe that is just where
they are supposed to be.
I do not think the issue is whether the printer is an HP printer, just
whether the escape sequences you send it are correct (and that it can even
accept configuration in this manner) - I think most all PCL capable
printers can do this (I have a Lexmark, and I use the same method for
passing enviromnent files to it that I do for HP printers).
At least as of MPE/ix 6.0, there are two ways to create an Environment
file: the "old" way with TTUTIL (which actually creates two files), and
the "new" way, which just amounts to creating a flat file by any means
(EDITOR will do) with the correct escape sequences in it.
Once you have a valid ENV file, just add the ENV=filename parameter to the
file statement for the print file you are creating.
If you created the ENV file the "old" way, you can see the name of the file
in the created spool file (at the very beginning); if you created the ENV
file the "new" way, you will see the escape sequences themselves at the
beginning of the spool file. In either case, if the escape sequences are
correct, they should produce the desired result at the printer.