Hi Marty,
thank you very much.
I also just tried it and it worked with this command

print "AssociatedDevices ".$res->valueof('//getUserResponse/return/user/associatedDevices/device/');
instead of
print "AssociatedDevices ".$res->valueof('//getUserResponse/return/user/associatedDevices/');
Now I also get back the associated SEP device which I also see in the GUI.
I make some further tests and write you back if I have some further problems.
Thank you so far.
BR
Michael