Mike, most of VB6 examples can be translated to VFP, in this case in the examples shown, ADODB and MSXML are used, and both can be used in VFP too.

Then, in the first of the links referenced, the example 2 uses again XMLHTTP:

See at point: "2. http request object"
http://www.motobit.com/tips/detpg_post-binary-data-url/

I think that using the first example, the second and the comments about the parameters order, you can get it.

Best regards.-