[udunits] Need to represent Celsius and Fahrenheit with C & F

• To: "udunits@xxxxxxxxxxxxxxxx" <udunits@xxxxxxxxxxxxxxxx>
• Subject: [udunits] Need to represent Celsius and Fahrenheit with C & F
• From: "Leek, Jim" <leek2@xxxxxxxx>
• Date: Sat, 10 Nov 2012 01:38:58 +0000

I want to use UDUnits2 with a Chemical Engineering simulator called Aspen Plus. 
 Aspen Plus doesn't require coulombs or farads, but it represents Fahrenheit 
and Celsius with F and C.  I thought adding these definitions would just be a 
matter of editing the udunits2-common.xml file like so:

...
                  <symbol>&#x2109;</symbol>   <!-- DEGREE FAHRENHEIT -->
                   <name> <singular>fahrenheit</singular> </name>
...

To

...
                  <symbol>&#x2109;</symbol>   <!-- DEGREE FAHRENHEIT -->
                   <name> <singular>fahrenheit</singular> </name>
                   <name> <singular>F</singular> </name>
...

And maybe I would have to delete coulombs and farads out of the 
udunits2-derived.xml file.  However, any attempt to do any of those things, the 
deletion of farads or coulombs, or the addition of new names "F" or "C" and 
udunits2 appears to fail to parse the XML file.
I don't think I'm messing up the XML, because I can add additional, more 
unique, names to Fahrenheit, like "earwax" or "degrees_Jim."  But "F" and "C" 
seem to be illegal.  I haven't dug into the UDUnits code yet, does anyone know 
how to get this to work?

Thanks,
Jim