Anyone know how the CRM data migration framework works?

I have in a test environment set up a new CRM 3.0 and populated it with
users and some basic data. With the SSIS in SQL Server 2005 I have populated
the Account table in the cd_mscrm database.

Then when I try to use the "CRM data migration framework" and the CDF
migrate wizard it says "The migration wizard completed succesfully". But no
data are migrated. The table says 0 cdf records, 0 migrated records and 0 non
migrated records. Still there are 3900 records in the account table.

Why is they not counted - what am I donig wrong?

Is there some flags causing this problem, because i worked once but with
faulty migration status. I have restored the CRM database to a pre migration
status also but with no luck.

I'm stuck!

Regards
Ulf