Is it possible to enable doorphone preview with T58W ?

[Xerox]

I'm trying to enable doorphone preview in T58W phone (while T58W rings doorphone camera is displayed before answering).

Doorphones are a Fanvil i62 and a Hikvision 8003-ime1

With a Fanvil V67 phone, ticking the "Enable preview" flag just makes it work with both doorphone models, so it isn't something proprietary.

I can't get it work with T58W

T58W has a "doorphone" feature settings area that supports Custom as well as other four brands (not my case).
I filled those informations (including also preview) and Early Media setting too.
No way...

When answering incoming call, video is correctly displayed, preview is the issue.

Any suggestion please ?