I finally got around to writing a document covering the entire XM Protocol Spec. This is for the XM PCR, XM Direct, and XM Commander. It is most likely most of them, if not all there devices, but I can vouch personally for the 3 mentioned. If any of you need help or have questions using this, post a comment with your return email address and I will get back to you.
If need I can post some sample C# code here using the spec.
Hope you enjoy and get good use out of the document.