go to conferences
user menue
edit your preferences
automaticall log in when you return

There is also an option in there that may be heopful:

Use MARK time stamp feature?
Select "yes" if you wish to use the MARK time stamp feature to keep track of new messages. In this mode, you manually mark forums when you finish reading all the messages in that forum. Otherwise, your last visit time stamp is used to keep track of new messages.