Importing Smartermail users into Plesk

HI....

I have the following problem/task

Server1: Plesk and Smartermail (both latest build).
Server2: Helm and Smartermail (both older versions).

How to "merge" these 2 servers?
I can easily move the SmarterMail domains from server2 to Server1 and get that part running, but then the domains/users are not sync'ed with Plesk

Does anyone know, how to import the domains/users into Plesk (or from the old Helm)?

Thanks


/Jan