[Moin-user] How to merge userdata when upgrading from 1.3 to 1.5

[Gisbert Amm]

We are currently runnung several instances of release 1.3.4 of MoinMoin 
and are about to upgrade to 1.5.2. ATM, each Moin has it's own userbase. 
We want to merge them into one with the 1.5.2 release, since it supports 
the use of one userdatabase for several Wiki instances. How can we 
achieve that with as less pain as possible? How shall we handle 
duplicate user profiles (of users that are currently subscribed to 
several Wikis)? Is there a migration guide or a howto somewhere?

Any hints are highly appreciated.

Regards,
Gisbert Amm