BI Site-minder SSO

Hi, we want to implement sitemider SSO for business objects 4.1

Do we need another webserver (apache) or can we use the existing BI tomcat.

Please share the steps if any one has already done it.

we are on BI 4.1, I found this thread and it says we need another web server http://scn.sap.com/thread/3176573

Thanks,

V