GALSync cross forest move - Duplicate

I am performing an Exchange migration to a resource forest using Linked Mailboxes. After the mailbox has been migrated the mailbox user remains as a mail enabled user. After the next GALSync is performed the new Linked Mailbox is synched back to the account forest as a Mail Contact. So now a contact and a mail enabled user exists creating a duplicate, which causes issues.

Another forum thread details the problem, and advised that it was able to resolve this by modifying the galysnc.dll

http://social.technet.microsoft.com/Forums/exchange/en-US/d0a27eb9-451d-450c-b887-488f68de3fbb/fim-2010-galsync-with-preparemoverequestps1#8b69684f-cc88-4039-9ef5-fc1b5df8e5ac

Does anyone know how to go about doing this? The forum thread was quite old and I am not sure if the person will respond.