[XeTeX] fontmapping configuration in .99b for Macintosh; diglot?

[Maurice Bauhahn]

Hello Friends,

Today I tried to create a mapping file so that all numbers of my text  
(in this case chapter and verse numbers) would be converted into the  
Khmer equivalent. My KhmerNumbers.tec compiled script works against  
text files when used separately on the command line (although  
interestingly I had to create individual entries instead of class  
entries for it to work).

Then I set about putting this KhmerNumbers.tec script in the previous  
place I'd had experience of placing such files: ~ /Library/texmf/ 
fonts/misc/xetex/fontmapping/

However in XeTeX for Mac .99b the path is apparently different:

/Library/teTex/share/texmf.local/fonts/misc/xetex/fontmapping/

In addition while assigning the fonts I added the mapping setting as  
follows:

\font\fourteenrm="Khmer OS:script=khmr:mapping=KhmerNumbers".

Unfortunately my output does not reflect the Unicode transcoding.  
Hence, may I assume XeTeX has lost track of the placement of these  
files? Is there some place to tell XeTeX where the fontmapping files  
are actually placed? Or is my font declaration faulty:-)

In addition, would any of you suggest any TeX scripts that could be  
used for creation of diglot books where it is important the two  
columns have roughly parallel content (so the more verbose language  
would have the wider column?

Cheers,

Maurice