transparent color on PIXMAP in JPG output

["André M. Winter - Carto.net"]

hello,

new to maperserver i am playing around with different WMS sources. till 
now i used a GIF output because it best handled the DEMIS source. adding 
some satellite image sources i am missing to much colors and i switched 
to JPG (also tried PNG).

the problem: i do have PIXMAPs used for SYMBOL definintion that have a 
transparent color defined. with JPG output this is no more the case and 
i get such a result: 
<http://www.carto.net/travel/mapservtmp/main_map_1123059303.93959.jpeg> 
(remaining green sqares). the symbols should look link this: 
<http://www.carto.net/travel/mapservtmp//main_map_1123059428.45835.jpeg> 
(wrong extension, this is a GIF) or  but here we see the missing colors 
in the background satellite image...

PNG output doesn't help 
<http://www.carto.net/travel/mapservtmp//main_map_1123059790.51955.jpeg>. 
using PNG instead of GIF PIXMAP doesn't change anything.

is this a GD or a mapserver problem?

fyi here are my OUTPUTFORMAT dedinitions

#OUTPUTFORMAT
#  NAME mapformat
#  DRIVER "GD/GIF"
#  MIMETYPE "image/gif"
#  IMAGEMODE PC256
#  EXTENSION "gif"
#END

#OUTPUTFORMAT
#      NAME mapformat
#      DRIVER "GD/JPEG"
#      FORMATOPTION QUALITY=80
#      MIMETYPE "image/jpeg"
#      IMAGEMODE RGB
#      EXTENSION "jpg"
#END

and that's the way i define symbols

    SYMBOL
        NAME "gp_icon_plus"
        TYPE PIXMAP
        IMAGE "gp_icon_plus.gif"
        TRANSPARENT 1
    END



thank you for information hereon,


-- 
___________________________________________________________________
andre m. winter,
 cartography for internet and multimedia applications
 a6091 goetzens, tyrol, austria
 tel.: ++43.5234.32732
 email: <winter at carto.net>

<http://www.vectoreal.com/>          SVG consulting and development
<http://www.carto.net/>          online cartography focusing on SVG
<http://www.carto.at/>     print and online touristic map solutions