Exploiting Session Fixation on ASP

[pentest pentest <pentest108 () gmail com>]

Hi guys,

Just a quick question. I've found a few places (e.g.
http://www.owasp.org/index.php/Session_Fixation_Protection) where it's
mentioned that ASP applications are vulnerable by default to Session
Fixation. However, how do you exploit this vulnerability in real life?

On PHP you just use something like http://site.com/?PHPSESSID=something

But on ASP, you cannot do something like
http://site.com/?ASPSESSIONID=something because it will not work.
So, how do you exploit Session Fixation in real life?

Thanks in advance and have a nice day,