[Proj] EPSG CS not supported, but the epsg file contains the correct definition

[SAEZ Laurent - SG/SPSSI/CPII/DOM/ETER]

Hi all,

I have to add support for new CRS in my mapfiles.

New EPSG code, 4559 (Projected CRS for French Antilles - Guadeloupe and 
Martinique) replaces 2989.
The ellipsoide is the only thing different (GRS80 instead of WGS84).

So I add the EPSG:4559 definition in my epsg file.
<4559> +proj=utm +zone=20 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m 
+no_defs  <>

I use MapServer 5.6.5 with proj 4.7.0 (on Debian 64bits).

When I call a GetMap using EPSG:4559 the image rendered is "wrong". 
EPSG:4559 and EPSG:2989 are almost identical and the images should be 
approximately similar.
So, I test my EPSG code with testepsg.

If I don't specify the epsg file location ('/opt/mapserver/bin/testepsg' 
EPSG:4559), I have :
"ERROR 6: EPSG PCS/GCS code 4559 not found in EPSG support files.  Is 
this a valid
EPSG coordinate system?
ERROR 1: Error occured translating EPSG:4559."

If I specify the file location ('/opt/mapserver/bin/testepsg' 
'/opt/mapserver/share/proj/epsg' EPSG:4559)  :
"Validate Succeeds.
WKT[/opt/mapserver/share/proj/epsg] =
PROJCS["unnamed",
    GEOGCS["GRS 1980(IUGG, 1980)",
        DATUM["unknown",
            SPHEROID["GRS80",6378137,298.257222101],
            TOWGS84[0,0,0,0,0,0,0]],
        PRIMEM["paris",2.3372291666985],
...
...
...
UNIT["Meter",1],
    PARAMETER["standard_parallel_1",46.8]]
PROJ.4 rendering of [/opt/mapserver/share/proj/epsg] = +proj=lcc 
+lat_1=46.8 +lat_0=46.8 +lon_0=2.33722917 +k_0=0.99987742 +x_0=600000 
+y_0=2200000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +pm=2.3372291666985 
+units=m +no_defs

ERROR 6: EPSG PCS/GCS code 4559 not found in EPSG support files.  Is 
this a valid
EPSG coordinate system?
ERROR 1: Error occured translating EPSG:4559."

I use to add EPSG codes in my mapfiles. It's the first time I have this 
problem.

It seems that sometimes it is not sufficient to add a definition in the 
file EPSG...
I have read this thread ("Unsupported SRS but available in epsg file") :
http://www.mail-archive.com/gdal-dev@lists.osgeo.org/msg04926.html

My GDAL_DATA environnement variable is well defined. I tried to add the 
definition in cubewerx_extra.wkt without success.
Any idea ?

I send this message on this list but I can't know what application is at 
issue: GDAL or PROJ?

NB: I apologize for my bad English.