long running process in ASP.NET page

[ob]

The situation I have is that I have a long running process (that takes 15 min
to process) kicked off from an ASP.NET page. I launch a thread and kick of
the process and return instantly. I store information about the thread in
the session variable, which allows the user to login later and see what the
status of that process is. I would like to use a web garden, however the
round robin assignment of requests to the worker processes won’t work for me,
because I need subsequent requests on the same session to go back to the same
worker process. How can I override the round-robin assignment, (ISAPI?), or
how can I solve this problem. NOTE: I will have the same problem when I go
to a web farm, my strategy is to have requests from one session to go to the
same server and then to the same process. I understand that this limits
scalability slightly; however, I am fine with this, I just don’t know how to
make it go back to the same process…

How can this be done?

Thanks