Since Vray 4 is in closed beta, I imagine it will take a while before certain third party plugins, become compatible with it and the fact that the licence for those trying it out, ends in April 2018 and with all the changes that will inevitably take place, between now and then and until the full release etc, I would not expect iToo to be racing to get their plugins working correctly, with it, until whatever tweaks they are making to the SDK are finalised.. Could find you create a fix and suddenly a few weeks later, an new beta comes out and breaks it again.. It is a pity that Vray 4???, for now isn't compatible with FPP and RC etc, since to try out Vray Next (as it is called) you need to install it in whatever Max version you are using, which is my case is Max 2014 and since I need to have working FPP and RC plugins, my only choice is to install the beta in a different Max version, which is annoying, since I have spent a long time, setting up 2014, to work the way I like and installing all these plugins etc that I have invested in. So while the announcement of Vray Next, is great news and the future looks very interesting, in 2018.. I for one would rather wait until it is much closer to becoming a final release.. before FPP and RC are once again made compatible.
Were this a new full release, then I could see everyone wanting FPP and RC working properly.. but it is a beta and while iToo would obviously like to know what has changed, to be prepared and start looking into fixing things, for the new version. I do think it's a bit too early, while it's still in early beta testing.