customizing epsg codes

[Sebastian Walter]

Dear list,

I'd like to set up a wms mapserver with planetary maps, more precisely
Mars. There are the standard IAU definitions for the ellipsoid, e.g.:

49900,GEOGCS["Mars
2000",DATUM["D_Mars_2000",SPHEROID["Mars_2000_IAU_IAG",3396190.0,
169.89444722361179]],PRIMEM["Greenwich",0],UNIT["Decimal_Degree",0.0174532925199433]]

as well as for projections:

49910,PROJCS["Mars_Equidistant_Cylindrical","GEOGCS["Mars
2000",DATUM["D_Mars_2000",SPHEROID["Mars_2000_IAU_IAG",3396190.0,
169.89444722361179]],PRIMEM["Greenwich",0],UNIT["Decimal_Degree",0.0174532925199433]],
PROJECTION["Equidistant_Cylindrical"],PARAMETER["False_Easting",0],PARAMETER["False_Northing",0],
PARAMETER["Central_Meridian",0],PARAMETER["Standard_Parallel_1",0],UNIT["Meter",1]]

These are already incorporated in Arc WMS, so there are Mapservers which
spit out the IAU2000 srs codes in their GetCapabilities:
http://www.mapaplanet.org/explorer-bin/imageMaker.cgi?map=Mars&request=GetCapabilities&version=1.1.1
There is a proposal to OGC conformity of these codes:
http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1931.pdf

Could anybody explain me if there is a way of importing them into my
mapserver application? When I do:
METADATA
        "wms_srs"    "IAU2000:49910"
        "wms_name"    "mars_viking_color"
        "wms_server_version"    "1.1.1"
        "wms_format"    "image/gif"
END

I get the following error:
msBuildWMSLayerURL(): WMS connection error. Layer must have an EPSG or
AUTO projection code (in its PROJECTION object or wms_srs metadata)
Can't I include the IAU2000 codes somewhere in my proj setup?

The projection definition of my MAP is this:
PROJECTION
    proj=latlong
    pm=0
    a=33961900
    b=33762000
END

Which should fit to the IAU2000 definitions. As you can see, the wms
from the link above supports also EPSG:4326 for compatibility, but when
I import the layer with this, it's missing some degrees in the southern
hemisphere.

Any comments would be greatly appreciated.

Regards,
Sebastian