How does Migration Manager handle the SIDHistory attribute that already has values on the source (4210488)

What is going to be the value of the SIDHistory attribute on a target migrated or synchronized object if the corresponding Source object already has a value(s) in it's SidHistory, as a result of previous migration?

The SIDHistory attribute in Active directory is used to store the previous SIDs of moved objects such as users and security groups. This property can hold multiple SIDs. If one or more SIDHistory values already exist on the source object the behavior of Migration Manager during migration and synchronization is as follows:

1. "Add SidHistory" option is selected on the Migration or Synchronization properties. As a result all previous plus new SIDHistory values will be stamped on the target object.

2. "Add SidHistory" option is NOT selected on the Migration or Synchronization properties. No SIDHistory values will be present on the target object. This attribute will be skipped.

NOTE: When running SIDHistory cleanup for given Migration Manager project, it will only clear the value that was inserted during migration with this specific domain pair. Refer to Microsoft KB article ID 295758 on cleaning this Attribute with the script: http://support.microsoft.com/default.aspx?scid=kb;en-us;295758