Thanks, Rick. I had already tried this and yes, the two incriminated 'characters' are working this way; \x15 for Nonbreaking Hyphen and \x12 for Thin Space. However, as soon as you try to edit such a variable, (\+ and \st as it appeals in the dialogue) display as + and st in the document and this sticks...
For my application where it is not intended that these variables are touched by the ordinary UI, this behavior would not harm.
However: While in the test script this method works, implemented in the full script it does not work correctly!
It will be quite tedious to find out where the process breaks (debugging scripts is not that well supported - You know that).