ICO file format

BlitzMax Forums/BlitzMax Programming/ICO file format

I'm trying to find the ICO file format specification, but all I can find is information on the header and a lot of information of the new PNG-based ico files for vista, wich are not compatible with XP.
Does anybody have the Windows XP 32-bits per pixel uncompressed file format specs for an ICO file? I have all the pix.map releated data and I want to output this data in a simple single size ICO file.