As the subject says, the integrate_register_after hook is not called if a user is registered using the admin interface. This means that integrations would not be aware of those members being added. Probably not the way it would work.
I think
// If they are for sure registered, let other people to know about it
call_integration_hook('integrate_register_after', array($regOptions, $memberID));
Should also be placed above these lines in registerMember() in Members.subs.php
// All admins are finished here.
return $memberID;
So that the integration function is called whenever a member is registered.
See also http://www.elkarte.net/community/index.php?topic=1198.0 in regards to a conflict with the naming of this hook.
And here it is the fix:
https://github.com/emanuele45/Dialogo/commit/86f6dbd190bd1ebf03fd29f8207b999082f05aa8
I preferred to keep just one call and use an else to skip what should be only for the non-admin interface.
Updated the commit, in the previous there was a mistake... :-[