Scite and NSIS

I can't seem to get nsis.properties to do much in Scite. All the other languages work fine except this one. It's not showing in my languages menu and doesn't seem to affect the display of *.nsi files at all.

Strangely, Sc1 seems to load it's internal copy of nsis.properties, but won't use the copy in my Scite folder. i.e. I can't edit how it's displaying NSIS files.

Any ideas?