Domains consolidation using ADMT V3

Hi Folks,

Due to multiple accusations our company has had we have a few legacy NT and few 2003 domains and we have begun looking into consolidating into one forest. Prior to my involvement with this project, we had outsourced to an identity management company to work on getting the test accounts migration using ILM (don't know why). They have come back to us requesting us to test the password synchronization of the migrated accounts using ADMT. I am reviewing the ADMT v3 (300 page doc) in which it mentions about the Password Export Server service which can be used for the migrations of the passwords. My question however are these :

Is ILM widely used for migration ? I thought it served another purpose for multiple directory services and that we should have used ADMT in first place and it would allow us to do the both i.e accounts and passwords migration.
Is there a way I can use PES to only sync the passwords for these already migrated accounts ?

Is there a documented reference somewhere on this. The ADMT guide does not into the details for PES.

You help is appreciated.

Regards,
Scharique