Update 10/4/2007: Since this post has been published, we've updated the Exchange 2007 Autodiscover Service whitepaper to include this information. Please consult the whitepaper for most up-to-date ...
Updated Jul 01, 2019
Version 2.0
Blog Post
I am missing a method using ISA 2006. You can create a single listener with two IP adressess, and on each IP address a particular certificate is mapped (e.g. mail.contoso.com on the first IP address and autodiscover.contoso.com on the second IP address). Then you should not omit entering autodiscover.contoso.com in the Outlook Anywhere rule (Public Name tab).