Use of different epsg code

[antonio]

Hi ,
I am new of mapserver. I am using mapserver for an astronomic 
application and I would like to use Mollweide projection ( epsg:54009).
I am able to draw the graticule ( the ellipse  )  using this layer 
inside mapfile.
First of all in the top of mapfile I defined these :
MAP
   NAME ASTRO
   STATUS ON

   #EXTENT -180 -90 180  90    EXTENT -18000000 -9000000 18000000 9000000
     UNITS dd
   #IMAGECOLOR 0 123 123
   TRANSPARENT ON
   SHAPEPATH "G:/GalexData/TestPoint"
   CONFIG "PROJ_LIB" "E:/ms4w/proj/nad/"
.    PROJECTION
           "init=epsg:54009"
     END

.
.
.

The layer definition for the graticule:

LAYER
  NAME "Grid"
  METADATA
    "DESCRIPTION" "Grid"
  END
  TYPE LINE
  STATUS OFF
  CLASS
    NAME "Graticule"
    COLOR 123 123 123
 END
 PROJECTION
     "init=epsg:4326"
     #"init=epsg:54009"
 END
 GRID
   MAXARCS 1
   MAXINTERVAL 15
 END
END # Layer


So this work but I don't really understand why I have to define the 
EXTENT as -18000000 -9000000 18000000 9000000 and not as -180 -90 180  90
and in the layer "Grid" definition I cannot define the init=epsg:54009 
but init=epsg:4326 . If I use 54009 , mapserver goes in stall , it gets 
98% of CPU and don't end never.
If now I want draw one polygon shape on this map and I use this layer :
LAYER
 NAME "TestPoint"
 TYPE POLYGON
 STATUS ON

 DATA TestPoint
 PROJECTION
       "init=epsg:4326"
 END

 LABELITEM 'tilename'
 DUMP true

 CLASS
   NAME "TestPoint"
   STYLE
     SIZE 2
     OUTLINECOLOR 123 123 123
     COLOR 0 0 255
       END
   LABEL
     MINFEATURESIZE 200
   END

 END

  METADATA
     GML_INCLUDE_ITEMS "tilename,survey,ra,dec,nuvexptime,fuvexptime"
     WMS_SERVER_VERSION "1.1.1"
     WMS_FORMAT "image/png"
     WMS_TITLE "Galex AIS Survey"
     WMS_ABSTRACT "SDSS DR3 imaging level 0"
     WMS_SRS "EPSG:4326"
     WMS_NAME "TestPoint"
    #WMS_FORCE_SEPARATE_REQUEST "0"       END
    END

and here too , I have to use epsg:4326 and not 54009.

There are someone that could help me about this and If I want to change 
the projection from Mollweide to Aitoff  , is it possible and supported 
by mapserver.
Thanks
Antonio