I usually do projects like this:
At “Test Plan” create:
- Thread Group - define how many threads you want to use
- Save Response to a file - to have result for some analysis (I usually created java programs to have some additional statistics from the results)
- HTTP Authorization Manager - to define user name and password for IS
- Graph Results
- View Results Tree
- Aggregate Report
Inside Test Group you need to put HTTP Request, where you can define, server, port and what service you want to invoke.
If you want to check how to use elements in JMeter - please see help at this program - it is quite good documented.
If you want to some examples - please give me your email address and I will send some examples for you 
Regards,
Lukasz Konkol
#webMethods-General#webMethods#Integration-Server-and-ESB#webMethods-Architecture