Adding letters to a font

I'm using FOG 5.1.4 on a PC to attempt to add Central European letters to a commercial font that I own, for my own use, letters like the cacute (dec 263, unicode 0107). While some fonts accept the letters with no problem, on this particular font I add the letters in FOG and then generate a font -- but the letters aren't recognized by Windows (if you go to the Windows character map for the font, they aren't visible there), nor can they be called up by any of my word processors). Is there some code that needs to be changed to tell Windows that the generated font now supports the Central European character set? I've got it set right now for Win 95 (rather than Win 3.1 format), which seems sufficient for most fonts. What else do I need to do to make the new letters functional?