Session State (Web.Config)

Does anyone know how to programmatically change the web.config's timeout property for Forms Authentication?

I have a few different seminar types and only one of them gets a 30 minute timeout the others are 60 minute timeouts.

I tried this:

if (seminarcode == 2)
{
Session.Timeout = 1; (for testing purposes)
}

This only sets it so that the page timesout after 1 minute of no use where I want to make everything cease after a minute no matter what the user does.

I thought I had the answer but it appears I do not.

PLEASE HELP!

also... what does "hth" mean?

Dave