Jukzh's script does work for mscim! Thanks a million!

When 'ONBOARD' is enabled, then auto-capitalisation and auto-completion is working. Also, and this is very valuable, Fn-Ctrl (Sym) brings up the symbol keyboard. However, I could not access the 'normal' alphabet keyboard.

What the script does not do is remove/stop the SCIM processes when 'ONBOARD' is enabled. Stopping SCIM, when not required, would be good for battery life...