FM8 and DITA -- Correct way to insert non-breaking spaces, etc.?

I've gone round in circle trying to figure this out.

FrameMaker's "good old" method of inserting a non-breaking space -- CTRL+SPACE -- doesn't work if the content is output as a DITA XML file: XML requires a string consisting of Ampersand-"nbsp"-semicolon (I can't enter the actual token because browsers evidently see it as a "real" non-breaking space...)

What's the trick for entering non-breaking spaces in content that will be saved as both:

• 
  
• DITA / XML
• 
  
• FrameMaker binary (.fm)
• 
  

Is this one of those ALT+keypad things? Or...?

Cheers & thanks,
Riley