The masters of have made a delicious wordfile for Ultraedit
6.x or higher ( that did an excellent hightlightning
of FlashMX 2004 AS 2.0 .
Beside the normal groups like strings, numbers, comments and text it
will highlight keywords, classes, functions, methods, properties and old
desperated syntax.

Best of all its FREE, grab it here:

About installation copy it into your wordfile.txt at unltraedit
directory or read the ultraedit help.

Thanx to Hausmeista and Ston3d!