This is one for those afflicted by the mighty and mightily dreadful titleformatting syntax of fb2k...

I have converted my Perl script that translates from something almost readable to the fb2k format into an AutoIt3 script and compiled the latter into an exe file. The zip contains the upx-packed exe and the au3 source.

If your editor of choice can be configured to call a compiler for a defined file type, you could "compile" your .txt files (or whatever, the program accepts everything) to produce a .tf file (or whatever).

Then copy the content of the output file into the relevant fb2k titleformat dialogbox... et voila.

The "conversion" is extremely simple-minded but pretty effective. See also this thread.