Technically, all you need is to add correct extensions to your certificate, which will identify it as an EV certificate. CA/Browser forum defined one in https://cabforum.org/wp-content/... (section 9.3.2).
A list of extensions used by particular venders is here: Extended Validation Certificate - Wikipedia
I guess you can argue that you extensively validated your certificate, but it will be hard to persuade others so. :)