[edit]
Here we go...

http://msdn.microsoft.com/en-us/library/windows/desktop/bb943991(v=vs.85).aspx#File_Layout1
 
This explains how the file is laid out. DDSURFACEDESC2 is depreciated. Use DDS_HEADER instead.

Can't you define a struct the same as DDSURFACEDESC2 but replace the LPVOID with LPVOID POINTER_32 instead in that case?

EDIT: That's a hack of course, but better than reading fields one at a time.

That would work... Until you try to read a DDS file that was saved with a 64-bit pointer.

I couldn't find a good answer on Google, but I find it hard to believe that Microsoft would be unaware of this issue.