I don't work at a software company. Rather, it's a small company that has a web site that happens to require a programmer for many tasks. So it didn't take much convincing to be allowed to release a few module I created at work (such as HTML::Template::Dumper).

One thing you might try is that just by using Perl, you've already benifited enormously from Free Software development. No doubt you've used other CPAN modules to add onto Perl's base functionality, which is another enormous benefit to your company. You're essentially working off perhaps millions of dollers worth of developer time for free. Is it not reasonable to contriute something back into that pool?