Based on what I understand, support is not planned for IA64 as the customer uptake for IA64 has been relatively low.  x64 is a more popular customer choice due to the better application compatibility and wider server support.

See this quote from this thread.

http://forum.sysinternals.com/forum_posts.asp?TID=4524

For any tool. We view IA64 as a dying platform despite HP and Intel's multibillion dollar effort to keep it alive. Just 20,000 IA64 systems sold in Q4 of last year.