Browser x.509 merging - developer Assist

I have developers seeking assistance with merging x.509 cert with person
document in names.nsf.
They are looking for the most direct method(s) to accomplish this via
web browser.
The functionality they are trying to achieve would not involve steps
like the old R6 admin4 manual acceptance of the certificate merging.
The desire is to have no manual approval steps and allow merging of the
certificate without additional add-ins or tasks outside of Domino.
Server platform is Domino 8.5.2 FP4 or 9.0.

If there is guidance that can be provided it would be appreciated.