SRS setting for a non-EPSG coordinate system.

[Bob Basques]

All,

Is there a way to get an arbitrary coordinate system output from 
Mapserver WFS (non-EPSG) using the same coordinate in the call to mapserver?

I can get the Capabilities request to show the correct coordinate BBOX 
numbers, but I still need to send in a UTM box to retrieve by.

How many locations are checked for the EPSG codes?

We see them in MapServer, GDAL, OGR support files, are there more 
locations.   Just trying to figure out how to best add in our local 
coordinate system as a WFS service to the EPSG code list.  (which BTW is 
"Minnesota Ramsey County, Feet").

Can a free form description of coordinate system projection in the 
mapfile work, we couldn't get it to work.

Is there some "non-projected" code that can be used to output the native 
values from the WFS service.  We get an error also if no SRS is 
specified in the MapFile.

Thanks

bobb