Hi Thomas,
From your description it sounds like you have an Exchange AD site that contains GCs that are NOT in the same domain as the mailbox-enabled users. If there are any home-domain GCs in AD sites that are directly connected to the Exchange server's AD site, then DSProxy will refer the mailbox-enabled user's Outlook client to one of those GCs.
If you have no home-domain GCs in any directly connected AD site of the Exchange server or within the Exchange Server's AD site, then DSProxy cannot refer the Outlook client to a GC of the same domain as the mailbox-enabled user.
DSAccess' incarnation list will only contain 10 AD servers in-site, or 10 AD-Servers out-of-site if all in-site servers are down. But DSProxy has a list of ALL AD servers in ALL directly conencted sites and only uses membership in the incarnation to assign points to servers.
Ross