Possible to pass a session_id to instantiate DB_Session library?

[eluser]taewoo[/eluser]
The reason for my asking is that I have a shopping cart associated with a session_id. I do credit card processing with PayPal but the problem is that PayPal IPN (that's PayPal server telling yours that payment has come thru) calling your server creates a DIFFERENT db_session object (b/c to the server it looks like a new user is coming to it) thus different session_id.

Is it possible to instantiate the DB_Session library by passing it an existing session_id?