Problems creating the right GeoTIFF-Header

Hello,
I am experiencing some Problems while creating a GeoTIFF Header for
SatellitImages. It looks pretty good in the TNTatlas, but yet far from
perfect. In all the other GIS programs I tested it with, the upper
left pixel has the right coordinates, but going south, something goes
wrong. I think it's some kind of problem concerning the projection.
I'm also not shure about the ModelPixelScaleTag and don't know how to
calculate or find out. In opposite to TNT, the other programs don't
get, that the upper left and right / lower left and right pixels don't
have the same Latitude. Up to now, the header looks like this and I
would be really glad if someone could give me a hint or even a
resolution for the problem:

Geotiff_Information:
Version: 1
Key_Revision: 1.0
Tagged_Information:
ModelTiepointTag (36,3):
...lots of Tiepoints...
ModelPixelScaleTag (1,3):
0.025690 0.025690 0
End_Of_Tags.

Keyed_Information:
GTModelTypeGeoKey (Short,1): ModelTypeProjected
GTRasterTypeGeoKey (Short,1): RasterPixelIsArea
GeographicTypeGeoKey (Short,1): GCS_WGS_84
GeogLinearUnitsGeoKey (Short,1): Linear_Meter
GeogAngularUnitsGeoKey (Short,1): Angular_Degree
ProjectedCSTypeGeoKey (Short,1): User-Defined
ProjectionGeoKey (Short,1): User-Defined
ProjCoordTransGeoKey (Short,1): CT_LambertAzimEqualArea
ProjLinearUnitsGeoKey (Short,1): Linear_Meter
ProjStdParallel1GeoKey (Double,1): 50
ProjStdParallel2GeoKey (Double,1): 65
ProjNatOriginLongGeoKey (Double,1): 13.072567
ProjNatOriginLatGeoKey (Double,1): 53.3297157
ProjFalseEastingGeoKey (Double,1): 0
ProjFalseNorthingGeoKey (Double,1): 0
End_Of_Keys.
End_Of_Geotiff.

Projection Method: CT_LambertAzimEqualArea
ProjCenterLatGeoKey: 53.329716 ( 53d19'46.98"N)
ProjCenterLongGeoKey: 13.072567 ( 13d 4'21.24"E)
ProjFalseEastingGeoKey: 0
ProjFalseNorthingGeoKey: 0
GCS: 4326/(GCS_WGS_84)
Datum: 6326/World Geodetic System 1984
Ellipsoid: 7030/WGS 84 (6378137.00,6356752.31)
Prime Meridian: 8901/Greenwich (0.000000/ 0d 0' 0.00"E)
Projection Linear Units: 9001/metre (1.000000m)

Corner Coordinates:
Upper Left ( 6.99084091,66.7100449)
Lower Left ( 8.78475189,55.6633263)
Upper Right ( 34.1365929,65.4713516)
Lower Right ( 27.2361317,52.1166649)
Center ( 19.2410000,59.7466000)