[ns] How to set fid_ of HTTP flow?

[Kennypounds <kennypounds@sina.com>]

Hi, dear users,

I go through the HTTP related script. But I can't find what i want.
I don't know why the HTTP related codes are all hard to understand
and use.

Simply, I need to define a "proc build-http { src dest fid }" to create a
http connection. I found that the code
"set httpSession1 [new HttpSession $ns $numPage [$ns picksrc]]"
in ~/tcl/ex/web-traffic.tcl is most simple to use. But it pick a source randomly
and no fixed fid_ assigned no fixed destination for a connection. fid_ is
important for me to seperate flows. But when I use 
	hdr_ip* hip = (hdr_ip*)p->access(off_ip_);
	int flowid  = hip->flowid();
to get flowid, i can only get the objectId_ not fid_. 

Who can tell me how to achieve my goal. Or who are so kind to send me 
some Web simulation code?

I appreciate your help very much.