Well, there are all kinds of possibilities where Cannistraro could have gotten it from. It couldn't have been a public source, not at that early date. I was speculating that, since he was ex-CIA, someone he had known at the CIA could have fed him the information. An active CIA person couldn't go public with that kind of information, but Cannistraro wouldn't be hampered in that way. So if someone in the CIA wanted to get it out, feed it to Cannistraro.
"How did Castelli pass on the the the exact text of the forgeries"
When did Castelli pass on the text? The CIA had supposedly been given the text - the text, not the documents themselves - sometime in late 2001-early 2002.