Discussed with Michael off-the-list and found that he has different setup where iked(8) is not involved.
Just in case, my question is about OpenBSD native iked(8) setup for remote access VPN gateway to serve OpenBSD native iked(8) client. If anybody has such setup and/or willing to discuss the details, please send me a message, I'd prefer to discuss this off-the-list. -- With best regards, Pavel Korovin