Dear all. Currently, I use 1 domain controller: ducnv.local 1 machine install Exchange 2003 (because required minimum hardware install exchange 2007 not met) 1 machine install TMG 2010 In local I access https://mail.ducnv.local/owa as success and send/receive email normal. But I need publish owa via TMG to user access go step select certificate authentication for weblistener then not availble certificate. Please help me. Thanks all.Thanks and BestRegard.!

I think you'll be better off posting this question in http://social.technet.microsoft.com/Forums/en-US/ForefrontedgePub/threads That section is specifically targetted at solving TMG publishing issues. However, what you need to do is either export your certificate from your Exchange 2003 (including the private key) and put it in the TMG local certificate store OR you buy a certificate, with a proper name (like webmail.ducnv.com) and put that in the TMG local certificate store. Then you'll be able to select the correct cert.http://setspn.blogspot.com