Secure Outlook Anywhere access to only domain-joined workstations

Hi all,

my company wishes to secure Outlook Anywhere so that only company supplied laptops that are domain-joined can access Outlook Anywhere externally - I have found this article

http://blogs.technet.com/b/exchange/archive/2010/12/06/more-whitepapers-to-help-you-securely-publish-exchange.aspx

which links to http://www.microsoft.com/en-us/download/details.aspx?id=23708 

This uses IPSec to secure access to Exchange, which will work but before I start going down that path I was wondering if there were any other ways of doing the same thing? We are running Exchange 2010 and Forefront TMG

Thanks!

Dylan