Outlook connects to other Exchange Servers (and not the local) for Public Folders

[Dirk]

Hello,

we are on the migration from exchange 2k to exchange 2k7. We installed
Exchange 2k7 in the same organisation.
At the moment we have 2 mayor sites on exchange 2k7.
The one in North Amerika has the problem, that Outlook hangs for longer
time, because it connects to old exchange 2k server regarding the public
folders.
In NA we created an extra PF store and in Europe we installed an extra PF
server. And we added both server on all PFs in exchange 2k as replicas (Took
some time untill all stuff was replicated).

Has anyone an idea, why outlook in NA so often tries to connect in europe
(echange 2k servers) to the PFs? (Setting on the NA server is done to point
to the local PF store).
Do I have to add the 2k7 server as replica to some System Folders?

Thanks in advance
Dirk