[otrs] Show ticket URL in a response

Hi guys, is there a variable containing the full URL of a ticket? I would need an auto-response in which to insert the full ticket URL so that the customer can simply click in the mail and be redirected to the ticket page (after authentication, obviously). Alternatively, could it be possible to append parameters to customer.pl to open a ticket as soon as the user logs in? Something like: https://support.isp.com/otrs/customer.pl?ticketid=1000123 Many thanks in advance. -- Claudio Tassini