There are two main ways to extend Felix: through scripting and customizing its templates.
I’m planning to set up a dedicated section of the website with useful scripts and macros for automating Felix. In the meantime, there are two that I recently wrote for Felix users.
HighlightGlossMatches
This Word macro will go through the current document, and highlight all terms for which there is a match in the currently loaded Felix glossaries.
Download HighlightGlossMatches
ReplaceGlossMatches
This Word macro will replace all the glossary matches in the current selection with their translations. It sorts the matches so that longer terms are replaced first.
To install one of the macros, first unzip it, and then from Word, press Alt + F11 to bring up the Visual Basic window. From Word 2007/2010, you could also go the the View ribbon, click Macros, and then click Create.
In the Visual Basic window, right click on Normal in the upper left window, select Import, and then import the unzipped macro module.
Incidentally, I’m also currently working on a tool that will make customizing the Felix templates easier. Stay tuned!