Web Transaction Monitor shows no transaction Data

Hello,

I've installed the Web Transaction Monitor into my Tomcat, and I am having difficulties to understand, how I could see the transaction Data of my WebApplication.
I've copied the WebTransactionAgent.jar into Tomcats bin-Folder and added in the Java-Options of Tomcat this line:

-javaagent:C:\Program Files (x86)\Apache Software Foundation\Tomcat 6.0\bin\WebTransactionAgent.jar

Now I've succesfully added J2EE Web Transactions in my Applications Manager (with localhost as host), but after I called some URLs of my Tomcat under localhost:8080, Applications Manager is in the Detail View of Web Transaction still saying "No transaction data available".

What I did wrong? I've running JDK 1.6 with Windows Vista.

Thank you very much for your help!

Tom