Printing level 1 PostScript from FireFox 1.5?

I have an old IBM 4029 printer, that can't handle PostScript Levels
2 or 3, not to mention unicode characters. Up through Firefox 1.06
or so, I'd been able to use a filter that would replace specific
Level 2 PostScript constructs with equivalent Level 1 forms, and
specific unicode characters with equivalent simple characters or
character sequences.

Believe it or not, it worked, because only a few Level 2 forms were
being generated. Likewise, I only ran into a few unicode characters
like left/right quotes and "...", which I was able to replace with
straight quotes and sequences of .'s. Note that these tricks didn't
work with the new versions of "acroread" which generate PostScript 2
in its full glory, so there are no simple substitutions I could use.

I just upgraded to FireFox 1.5 and I can't print any more. (1) The
printer properties menu no longer allows me to insert a Unix pipe
command like

	| convert_ps1.firefox | lpr -P localps

Where would I put such a command now? Would it go into one of the
".prefs" files? (2) I tried printing to a file, and then passing
it through the old filter, but it got flushed. I could go through
the steps of grep'ing for PostScript Level 2 & 3 keywords to see
if there were few enough that I find substitutes, but does anyone
out there know if it would work or not?

I'm running Linux RedHat RHEL 3. I'm not interested in solutions
that require rebuilding FireFox. Also, I'm going to see what other
kinds of printers I can scrounge in case there's no workaround.
Thanks,

	Carl Ponder