Or output_text_filter, rather

Oops! The sad thing is that I did a cut'n paste. My test code did not do the replace at all, but I didn't see it ;--( I'm glad I was close enough that you managed to get it right!

Which is why you (and by that I mean... I) should always write tests as real tests, using Test::* and comparint the expected result to the real one. That will save you embarrassment, and will prevent a few bugs every now and then.