Shot in the dark here, but I think, and I have not yet bought this one, but am planning on it:
I think, the database that supports this, is what we saw screen shots for. I requested that so I'd know what to build in mysql in order to import.
In another post, I shared how I get any database cleaned up to import to sql. Now, if you don't have access to import a file to sql on your server, you may be at a disadvantage with this one.
So for me, this is what I'd do:
Create a mysql table to receive.
Export an older list ( in my case dada mail)
Upload the list to new Powermessager
But, as I said, I've not purchased this yet, but I am tempted.
I think this should be added to PowerStore so those folks who purchased X product would be targeted to a specific purchase.