[OS X TeX] It is possible to use UCS free Unicode fonts with XeTeX (FreeSans, FreeSerif, etc)

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Greetings,

I'm writing my doctoral thesis, which includes a large amount of 
Classical Greek text.  I used to use the babel package with the 
"teubner" encoding, with MacOS Roman encoded files.  The "teubner" 
encoding was unreadable, so I switched to Unicode, so that I could 
actually see the Greek that I was quoting in my text.

The fonts I chose to use are from the UCS free font collection, i.e. 
FreeSans, FreeSerif and FreeMono.  XeTeX *will* produce PDF files using 
these fonts, if I use the command "\font\freeserif=FreeSerif at 12pt".   
The problem is that mktextfm cannot generate font metrics, and thus 
every time I generate the PDF file, it takes a good half a minute.  The 
log results I get are listed below. 

My question:  Has anybody been able to successfully install these fonts 
with XeTeX on Mac?  Or is there another font (say Gentium) that includes 
the full Unicode character range that *can* be successfully installed?  
I have searched everywhere for decent directions on how to do this, and 
have come up dry (I'm not willing to move to Context, because I don't 
want to lose my document classes).

Thanks in advance for any help...
Erik Norvelle
University of Navarra, Pamplona, Spain

Log file listing:

kpathsea: Running mktextfm FreeSerif

/usr/local/teTeX/share/texmf/web2c/mktexnam: Could not map source abbreviation F for FreeSerif.

/usr/local/teTeX/share/texmf/web2c/mktexnam: Need to update /usr/local/teTeX/share/texmf.tetex/fonts/map/fontname/special.map?

mktextfm: Running mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input FreeSerif

This is METAFONT, Version 2.71828 (Web2C 7.5.5)

kpathsea: Running mktexmf FreeSerif

! I can't find file `FreeSerif'.

<*> ...jfour; mag:=1; nonstopmode; input FreeSerif

                                                  

Please type another input file name

! Emergency stop.

<*> ...jfour; mag:=1; nonstopmode; input FreeSerif

                                                  

Transcript written on mfput.log.

grep: FreeSerif.log: No such file or directory

mktextfm: `mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input FreeSerif' failed to make FreeSerif.tfm.

kpathsea: Appending font creation commands to missfont.log.


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