The following Microsoft Outlook Web Access authentication methods are currently supported by BlackBerry Internet Service:
Microsoft Exchange 5.5
* Standard Authentication:
o Digest authentication
o Basic authentication
* NTLM (NT LAN Manager) authentication
Microsoft Exchange 2000
Note: Microsoft Internet Security and Acceleration Server (ISA Server) is supported with this version of Microsoft Exchange Server
* Standard Authentication:
o Digest authentication
o Basic authentication
* NTLM (NT LAN Manager) authentication
* Form Based authentication
Microsoft Exchange 2003
Note: Microsoft Internet Security and Acceleration Server (ISA Server) is supported with this version of Microsoft Exchange Server
* Standard Authentication:
o Digest authentication
o Basic authentication
* NTLM (NT LAN Manager) authentication
* Form Based authentication
Microsoft Exchange 2007
Note: Microsoft Internet Security and Acceleration Server (ISA Server) is supported with this version of Microsoft Exchange Server
* Standard Authentication:
o Digest authentication
o Basic authentication
* NTLM (NT LAN Manager) authentication
* Auto Discovery authentication
Microsoft Exchange 2010
Note: Microsoft Forefront Threat Management Gateway 2010 is supported with this version of Microsoft Exchange Server
* Standard Authentication:
o Digest authentication
o Basic authentication
* NTLM (NT LAN Manager) authentication
* Auto Discovery authentication
Source : http://www.blackberry.com/btsc/search.do?cmd=displayKC&docType=kc&externalId=KB23361