Adding a new lexer to scintilla/scite (...and eventually wxPython StyledTextCtrl)

Has anyone of you successfully added a lexer to scintilla?

I have been following the short instructions at http://www.scintilla.org/SciTELexer.html - and even discovered the secret extra instructions at http://www.scintilla.org/ScintillaDoc.html#BuildingScintilla (Changing Set of Lexers)

Everything compiles, and I can add the lexer to SciTE just fine, but my ColouriseMapfileDoc method just does not get called (a printf does not produce output). If I add the same code to e.g. the ColouriseLuaDoc lexer, everything is fine (a printf does produce output).

Specifically I have

1. In scintilla/include/Scintilla.iface, added val SCLEX_MAPFILE=99
2. And any lexical class IDs
3. In the scintilla/include directory run HFacer.py and confirmed that the SciLexer.h file has changed.
4. Created LexMapfile.cxx with a ColouriseMapfileDoc function

5. At the end of the file associated the lexer ID and name with the function:

   LexerModule lmMapfile(SCLEX_MAPFILE, ColouriseMapfileDoc, "mapfile");

6. Run LexGen.py to generate all the makefiles (as per the secret instructions)

7. Created a new SciTE properties file by cloning scite/src/others.properties
8. Set up some styles
9. In scite/src/SciTEGlobal.properties added $(filter.conf) to the definition of open.filter.
10. Added this language to the Language menu of SciTE,
11. Built both Scintilla and SciTE.
12. Grumbled and cursed.

What am I doing wrong, except maybe step 12?

In case someone reads this question in the future - you will also have to add a line import yourformat in SciTEGlobal.properties. That's the undocumented step 9b.