snapshot not copying network users to new install

Hi, I am using snapshot to migrate multisite blogs to single wp installs.
It is working well apart from the fact that it does not copy the network admin user - even if they are added as an admin on the multisite blogs. It only seems to copy users who are associated ONLY with the blog being copied.

Where a user is copied I am having to use phpMyadmin to edit the password/capabilites etc, login as that user then add myself as admin.

Am I missing something - i would really rather not have to do the phpMyadmin thing or have to add a new admin user (whose password I know) each time...

Many thanks