Dietmar Aust created an excellent bridge from Apex to JasperReports.
However, after following his directions, it still didn’t work.
After testing with the supplied Apex-application in the integration software we got the error
Datasource not found: default
After some digging we found that using the Tomcat 6 installation for 32 bits Windows did the trick. Installing on Tomcat 7 doesn’t work.