Hello Soban,
I can think of two ways for you to accomplish this task.
The first would be use rewrite the HTTP Host header from test1.cisco.com to test.cisco.com. Please see the Rewrite section of the configuration guide's chapter on Configuring HTTP Header Insertion, Deletion, and Rewrite for details on how to do this. I understand that you mentioned you already tried this, but this sounds like the most appropriate solution for this. Therefore, you should verify your config and perhaps get a network capture to see if the rewrite is not working, or if the rewrite is working but the server still isn't accepting it. If you do go with this option, then you may also need to make use of the header modify per-request feature to make sure it is done on every request, and not just the first.
The second option you have is to configure the ACE to redirect requests to the host test1.cisco.com to the host test.cisco.com. This would be largely transparent to the clients connecting to the VIP, although the address in their address bar of the browser would ultimately show the hostname that they were redirected to....test.cisco.com.
Hope this helps,
Sean