Hi,
As I see, the ServiceDesk plugin it is not designed to support the communication with a customer through more than user, because on customer portal there is no possibility to share between the users (from a client) the reqistered request, their status, etc.
Am I wrong? Are you planning such kind of faciltiy in this product? Without this functionality I am afraid JIRA it cannot be used like a helpdesk system, where there are reqistered customers / projects, customer users, and user A can see what user B reported, user A can see the whole request list from the company or can filter just on his list, etc - like how Mantis works.
Levente