Jason Jones, TMG firewall MVP put together a great article on things that you want to consider if you are planning to migrate from the defunct TMG to UAG.
Check it out at http://blog.msedge.org.uk/2012/09/initial-considerations-for-migrating.html
HTH,
Deb
DEBRA LITTLEJOHN SHINDER
MVP (Enterprise Security)
“MS SECURITY”
[email protected]