We've successfully implemented Blackberry Enterprise Server 4.1 on a Hosted Exchange 2007 infrastructure. Everything works like a charm which makes us very very happy!
However ... (here it comes)
when I do a lookup for a user from a device, we see the recipients from all the address lists on our Hosted Exchange servers. We really need to limit the lookup to include only recipients from the same organisation/domain name. I read in previous topics that this can be achieved by creating the necessary registry keys. I can't seem to find which registry keys should be activated.