Availability Services availability in the 2003 (AD&Exch) Account Forest

Hello!

My goal is to resolve the FreeBusy issues that accounts in the Account Forest are having when connecting to their Exchange 2010 Mailboxes in a new Resource Forest.  They log into their Account Forest and Outlook opens their linked Exchange 2010 mailbox in the Resource Forest.  The 2010 mailboxes are linked accounts to the accounts in the Account Forest.

At first I was looking at the Availability service itself (users cannot see free/busy data), until I remembered that it all ties into Autodiscover (point 1).

1. Autodiscover and Availability Services confirmed working within/inside the same Forest.  I logged on using a user account of the Resource Forest and onto computer that is part of the Resource Forest and began to create an Outlook 2007 profile. The Autodiscover service worked, and checking FreeBusy of other users in the Resource Forest worked.  So I know things are ok in the Resource forest.  (Not to muddy the water, but our Quest migration tool is bringing over the Exchange 2003 Public Folder data from our Account Forest and into Exchange 2010 Public Folders, and I was able to see this data as well!).

2. I have an AD2003 Account Forest.  This Forest actually contains our AD objects as well as our old Exchange 2003 organization/servers that we are migrating from.  So note that our Account Forest has Exchange 2003 installed and users that have not migrated are still using this Exchange Organization. 

In my Exchange 2010 lab, I have performed the task of populating an Account Forest with the SCP.  Shown in http://technet.microsoft.com/en-us/library/aa996849.aspx.  Worked no problem.

My question is,  what affect will setting the SCP in the Account Forest have on my existing user base that is using the Exchange 2003 servers in the Account Forest?  After setting the SCP in the Account Forest, when I set up a new Outlook Profile for a user who is actually still on the Exchange 2003 server, will the Autodiscover Service try to configure the profile for the Exchange 2010 environment? (To explain, we are using Quest Exchange migration tools, and an account+mailbox does actually exist in the Exchange 2010 Resource Forest for every user account in Exchange 2003; they just don't use the account+mailbox until they actually get "switched")

So to summarize:

An Account Forest AD user logs on and opens Outlook which connects to their Linked Mailbox in Exchange 2010: No Autodiscover and no Availability. Holding CTRL down, right-clicking the Outlook taskbar Icon and choosing "Test E-mail Autoconfiguration" fails in every possible combination.

A Resource Forest AD user logs on and opens Outlook which connects to their local Mailbox in Exchange 2010: Autodiscover worked and all Availability.  Holding CTRL down, right-clicking the Outlook taskbar Icon and choosing "Test E-mail Autoconfiguration" is successful !

I want to run the Export-AutoDiscoverConfig in the Resource Forest to populate our Accoun Forest but I'm asking what the result will be for my existing Exchange 2003 users.  Hopefully this will help resolve the FreeBusy as well.

Thanks very much in advance!