Thanks both of you for your help, we were just a little concerned when the consultants we hired gave us the RIM article below but missing one vital part "One BlackBerry Enterprise Server cannot provide email redirection for two different Exchange organizations".
We have over a hundred Blackberry users and a 1000 email account spread over 4 countries and 23 sites, each site having to be moved over to AD one at a time due to the way our servers and network is setup. So when we were told that we would have to remove the BES and reinstall in the new org and while this was happening only the Blackberry users that had been moved over to AD would work, we were very shocked.
We could therefore understand why some people given this sort of news would scrap Blackberry's as they moved there users over to AD 2003 and give them push email instead. But we are glad to hear that two servers can be used to get round this problem that I'm sure lots of people are having. Please see below Blackberry's article on moving from org to org.
Thanks
SpannerMonkee
How To - Migrate BlackBerry Wireless Handhelds between two Exchange Organizations
Last Updated: 22 November 2005
Article Number: KB-02060
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Summary
This article applies to the following:
BlackBerry Enterprise Server®
Microsoft® Exchange
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Details
Migrating Microsoft Exchange mailboxes from an Exchange 5.5 or 2000 organization to another organization, while maintaining the BlackBerry Enterprise Server information does not work.
Currently, there is no known utility or method that will retain the BlackBerry Enterprise Server information in this scenario. The BlackBerry Enterprise Server service account mailbox stores a pointer to the Exchange Server Distinguished Name (DN) that cannot be migrated to another organization. This information is only retained, when using the Microsoft Exchange Task Wizard to move the mailboxes between Exchange servers within a site.
One BlackBerry Enterprise Server cannot provide email redirection for two different Exchange organizations.
Migrate BlackBerry Enterprise Server to a different organization
Remove the BlackBerry Enterprise Server software from the originating domain and organization.
Move users and mailboxes from one domain and organization to another.
Reinstall the BlackBerry Enterprise Server Software.
Add the BlackBerry Enterprise Server to the BlackBerrry Servers object in Exchange Administrator > Site > Configuration, if using BlackBerry administration extensions or into the appropriate routing group, if using BlackBerry Enterprise Server Management console.
Add the BlackBerry wireless device to the BlackBerry Enterprise Server.
Cradle the handhelds and generate an encryption key.