Error in BMP-FileHeader after conversion PDF -> BMP

Hi,

i'm actually coding a C++-Program which reads data from various file-types 
to do a little comparison.
I'm using ImageMagick to convert PDF to BMP (btw I'm really impressed by the 
great opportunities of ImageMagick, really good work I think...). After the 
conversion (using commandline "-depth 24 bmp3:file.bmp") to BMP, I try to 
read the Bitmap FileHeader with my C++-Tool, which is working fine with 
several other Bitmaps I created (well tested). However, the FileHeader isn't 
read correctly (incorrect signature and other values) if I did the 
conversion before. I'm suggesting ImageMagick doesn't write the 
BMP-FileHeader correctly. Is this possible and how can the problem be 
solved? Do I have to use other commandline-options especially for BMP? It's 
kinda strange that there are no problems in showing the created BMP with any 
software ...

Thanks in advance for any answer!

Best regards,
Tobi