The best thing for you to read to help you is the IBM RedPaper on CVP with WebSphere.
This is a huge document you can download from the IBM web site (ibm/redbooks - about 140MB) and it's good reading for anyone interested in CVP. It's especially good for those using WebSphere instead of Tomcat for the CVP VXML server.
One of the authors is Cisco's Jeff Wolfeld, who was (is?) a Technical Leader and lead architect for CVP.
The fullname of this redpaper is:
"IBM WebSphere Voice Server V5.1.2/V5.1.3 and Cisco Customer Voice Portal V3.1: An Interoperability Guide"
Regards,
Geoff