If you are using BES Express for Exchange Server you should check out, BlackBerry Enterprise Server Express for Microsoft Exchange Version 5.0 Service Pack 2 Maintenance Release 1.
This maintenance release should be tested and installed on to computers hosting BES Express, BlackBerry Administration Service, BlackBerry Attachment Service, BlackBerry MDS Connection Service or the BlackBerry Router.
“(DT 838289) In the initial release of BlackBerry® Enterprise Server Express 5.0 SP2, users with BlackBerry® devices running
BlackBerry® 6 are not be able to browse to their organization's intranet sites. This occurs because BlackBerry 6 handles browser
transport selection using a different method than previous versions of the BlackBerry® Device Software.”
“In BlackBerry Enterprise Server Express 5.0 SP2 MR1, the MDS Browser Domains IT policy rule has been added. You can use
this IT policy rule to specify the domain of your organization's intranet sites. After you apply the IT policy to BlackBerry devices,
users with devices running BlackBerry 6 can browse to the domains that you specified.”