I tried my other experiment - I took my custom config file, renamed it to simple.config, put it in the autoconfig folder, and it WORKED!!!
So, it seems there was/is something wierd about the ConfigurationPath command. The javascript error muttered about expecting a hex value around character value threehundred and something in the line generating the editor.
I'm still interested in knowing how to add new files to the AutoConfig enumeration list - so I can add my evil stuff without trashing the 'normal' ones.
Thanks again
time for bed....
Doug