XMLHTTP help for FedEx site

I'm trying to us XMLHTTP on a secure web page of FedEx. It's URL is

https://www.fedex.com/servlet/InvoiceServlet?link=4&jsp_name=adjustment&orig_country=US&language=english

I can get to this page OK using XMLHTTP, but can't seem to get to the next page when you "Make A New Request" (say with FedEx Express and FedEx Invoice checked off. After submitting that, I have trouble getting taking a tracking and invoice number and submitting that.

I'm sure it's my technique, or referer value, or SSL or something else, but I've tried so many combinations and nothing seems to pan out. Can someone give me some pointers or a code segment to get from page to page here?

I'm a relative noobie as far as the web GET, POST and protocols, (although I have no problem on UPS site doing similar things).

Also, if someone can recommend some good HTTP sniffer/monitors that would track these web actions that would be great. HTTPSpy & EffeTech HTTP Sniffer seem to only catch part of the transaction, although it may be a configuration issue.

Thanks in advance,

Ira