Trouble getting GeoTiiff transparent: what to use ? transparent, offset, transparency ?

[Steven De Vriendt]

Hi List,

I have trouble displayin a geotiff. I'm not quite familiar with raster images...
When viewing the raster in MapServer I get a black image.
When viewing the raster in ArcGIS I get an image but I have to set
display background value 1 as no data to make it transparent.

In my mapfile I set following options
TRANSPARENT ON (for the mapfile)

OFFSITE 0 0 0
TRANSPARENCY 0
that's for the raster layer itself.

Can anyone give me advice on how to get the black background which I
can see now transparent ?