...
Expand the tree and find the container you want to configure, input the value and click Update . After that, the Console will prompt that "The openejb configuration should be restarted for the changes that were made to the fields to take effect. The changed fields are now shown in red color."
To restart the openejb module on-the-fly, go to Application->System Modules on the left panel and check Expert Mode. Then find org.apache.geronimo.configs/openejb/2.2-SNAPSHOT/car
and click Restart to make your changes take effect.
!RestartinExpertMode!