I use GADS to synchronize and update user account information from an internal directory, to my Google Apps for Business account.
Within GADS, there is a field named "Unique Identifier Attribute", to which I have associated that field with an internal unique identifier.
This unique identifier attribute is synchronized to my Google Apps for Business account, along with other fields for each user account.
Using GAM, I cannot locate this field.
GAM provides a field named "Google Unique ID", which is most likely Google's unique ID for each user, not necessarily the unique ID for each user as per my setup in GADS.
All other information about each user is retrievable by GAM (first name, last name, email, etc.) save for the value in the "Unique Identifier Attribute" field in GADS.
Thoughts?