afaik, you cant.
the SyncScopeProvisioning will create a separate _tracking table to save the metadata for keeping track of the changes. The _tracking table not only keeps track of create/update timestamp but keeps track as well of the peer that created/update the row.
So while in theory you can probably rewrite the SelectChanges sp to retrieve the added/changed rows using SQL Change Tracking, SQL Change Tracking cannot provide the peer who created/updated the row.