You are looking for developer information and I linked you to the developer page at Xerox.com where you go to obtain that information.
Joe, I don't have an account but I will ask my collegue to take a look there. It would be helpful if you provide me more detailed information what exactly we should looking for there?
Pretty much got to go here and sign up for that sort of stuff.
I'm looking for any documentation about FreeFlow Print Server, especially regarding communication and retrieving information about actual printing jobs like JobID, number of pages, quantity, percentage of completion, number of already printed pages, number of already printed sets etc.