Enabling Client Driven migration filtering mailboxes on Employee-Type

If for some reason you want to enable mailboxes for client driven PST migration based on the Employee-Type attribute (given as an option by the enable client driven migration wizard) you will first need to add the EmployeeType attribute to you global catalog.

To do this follow these steps:

1.Open the Active Directory Schema snap-in. (you will need to be a member of schema admins)
2.In the console tree, click Attributes.
3.In the details pane, right-click the attribute employeetype and then click Properties.
4.Select the Replicate this attribute to the Global Catalog check box.

Allow at least 15 minutes for the change to replicate and then try filtering by employee-type again and you should now get hits (assuming you have already propogated the values for the attribute)

Reference http://technet.microsoft.com/en-us/library/cc737521(WS.10).aspx