Multiple instances of Tomcat

[Frank Diakovasilis]

I have come across this topic many times in this mailing list, but never
paid attention since I never needed to.... but I now need to run multiple
instances of Tomcat on a single server (IIS).  The only docs I came across
say to set a CATALINA_BASE variable, and that is all they say.  What steps
need to be taken to use multiple instances of Tomcat? What directories need
to be duplicated, and what files need to be changed? also I am using the
isapi redirect, what has to be done there? 
 
I'd appreciate any help, Thanks.
 
-Frank