I entered the non-breaking space for the author in the Manage Authors dailog. That was kept and I can see it is correctly handled on the device. In this case I used the keyboard to type it in (on the numeric keypad, hold ALT down an type 0160).
I just tested this in a plugboard. As I didn't want to mess up my authors, I put the following in and had it go to the Publishers field:
Code:
program: raw_list('tags', ',*')
That is a non-breaking space after the comma in second parameter. The forum software might change it.
When I sent a book with multiple tags, I could see the non-breaking space in the OPF of the book on the device.