Exchange Server - Mail Enabled Public Folders

Migration from Exchange 2003 to Exchange 2010 SP1.
On Exchange 2003, 5000+ of my 12000+ Public folders are Mail Enabled.
They appear in AD with e-mail addresses, they CAN (tested) receive
mail...even from Exchange 2010 mailboxes.

On Exchange 2010 (EMC and shell) about 4000 of the 5000 appear as
MailEnabled=$false .

I am guessing, but I THINK that it was caused because they had invalid
names (alias with blanks, leading and/or trailing blanks, etc.) which
have NOW been corrected.

If I try to Mail Enable the folder using the Public Folder Management
Console or the shell "Enable-MailPublicFolder" command, it creates a
second AD entry with a new e-mail address, CN, the whole nine yards;
but the  LegacyExchangeDN is identical which causes an ambiguous name
error (it will not receive mail).

Two questions:
1. Has anyone seen this?
2. Any ideas on how to connect Exchange 2010 to the already existing
AD entry?

Matt

OK, If anyone else runs into it...
http://support.microsoft.com/kb/977921 outlines the problem

There are 2 fixes:
for a small number of folders, disable via your pre-2007/2010 system
and re-enable with 2010.

for a large number,  you can try ExFolders (dated POST 2011/07/25) to
turn on the PR_PF_Proxy_Required switch.
I also used LDIFDE to stop the RUS from updating by adding
msExchPoliciesExcluded before flipping the switch.