IDAPI-Wrapper OpenSecurityCacheUpdater: How do I get it to work?

Migrateduser

We use iHub 16.2 and are evaluating the RSSE web service (the sample RSSE Implementation, no modifications made). In order to update the users and their roles etc. on iHub with the changed information from the remote system (which is retrieved by the RSSE service, in case of the sample implementation by reading the SampleRSSE.json file), I compiled the IDAPI-Wrapper OpenSecurityCacheUpdater from https://github.com/robmurphy/idapi-wrapper and ran:

     OpenSecurityCacheUpdater o 
              = new OpenSecurityCacheUpdater("http://localhost:8000/", "Administrator", "",  "DEFAULT VOLUME");
     o.invalidateCache();    //retrieves iHub User data from remote system via RSSE web service

If I run this, unfortunately in the Adminstrator’s view there are no changes visible on new login (Only if I stop the iHub service, restart the Tomcat with the web service and start iHub again, the changed users/user properties like roles etc. will appear in the Administrator’s view of iHub).
To figure out, why running the OpenSecurityCacheUpdater IDAPI Wrapper does not show the expected results, I checked the log4j output:

     There are 3 Exceptions of the same type:
     java.lang.NoSuchMethodException: org.apache.axis.encoding.ser.ArraySerializerFactory.create(
     java.lang.Class, javax.xml.namespace.QName)

which I guess are debug messages only. There are 3 SOAP messages in the log:

    One which contains
    <Login xmlns="http://schemas.actuate.com/actuate11"><User>Administrator</User><Password></Password></Login>
    and 2 others that contain
    <AdminOperation><UpdateOpenSecurityCache/></AdminOperation>

I cannot see what’s wrong in the log4j output.
Also, I checked the iHub log file. In the iHub log file, the only RSSE thing that appears on running the OpenSecurityCacheUpdater is the following command:

    CONFIG: Start RSSE purging for volume "default volume"

(What does RSSE purging mean?)

I use the Sample RSSE implementation from OpenText with no modifications. In the provided SampleRSSE.json file, the name of the default volume is “DEFAULT VOLUME”.

The idapi wrapper uses Axis 1.2.1 while the RSSE service seems to use Axis 2 v1.6.2.
Is the OpenSecurityCacheUpdater compatible with iHub 16.2?

Since I have no experience with SOAP, I have no idea how to figure out why the Update OpenSecurityCache command does not work.
Therefore I would like to ask if someone can give me a hint or guidance on how to proceed. Thanking you in anticipation.