OK, found the adapter on Steve website.
I was also told that Pinsound adapter does work, and since I have a Pinsound in my LOTR I already have the cable.
So next question is: as I intend to replace Pinsound with TiltAudio in my LOTR (primarily because P...d is completely closed and does not allow to hook up on their expansion port, despite the fact it's present, that they are using community orchestration for Shakers - so called shakerization - but obfuscate them and integrate them into their firmware without giving credit to the original authors, etc), I already have the cable so don't need an extra one.
So which kit can I order to get Whitestar support ? I'm assuming WPC ?