Add the new role qadadmin in TOMCAT_HOME/conf/tomcat-users.xml as follows:

For Tomcat version 6.0.29 and before, make sure that the manager and qadadmin roles are associated with the administrator user. The final result looks like:

For Tomcat version 6.0.30 and later, make sure that the manager-gui, manager-script, and qadadmin roles are associated with the administrator user in the same file. The final result looks like: