Cross Forest Exchange Migration - 2003 SBS to 2010 Exchange

We are attempting a Cross Forest Domain and Exchange migration. There is an existing 2003 Small Business Server  and we going to a Windows 2008 R2 network.

The network is currently setup like this:

• Existing.local domain
  • SBS2003.existing.local
  • 2003STD.existing.local =  32 bit Standard server with the FSMO rolls seized.

• New.local domain
  • tempdc.new.local   = (Active Directory  Domain Controller on Windows Server 2008 Standard)
  • main.new.local  (File server and future Domain Controller on Windows Server 2008 R2)
  • mail.new.local  =  (Exchange 2010 on Windows Server 2008 Standard).

The entire new domain and Exchange Sever is up and running. We have setup trusts and used Microsoft's ADMT and is working well. I have used the move-mailbox command with Exchange previously and read that now we must use New-MoveRequest cmdlet. This did not yield the results TechNet claimed. We used the Prepare-MoveRequest script provided by Microsoft  and we now have user accounts that are placed in the Exchange Mail Contacts, but nothing in the Mailboxes.

Does anyone know what I missing to get accounts migrated into Exchange?

Please note, creating PSTs is not an option as we would like to keep the CN names linked to all the archived mail items for the purpose of future use editing.