Ok, based on my previous experiments I can describe a workaround to work with Play under VE Pro 4881.
Basically the idea is to create the VIFRAMEs involving PLAY under VE Pro 4686, then use them under VE Pro 4881. Thus what I'm suggesting is to use 4686 just to edit the VIFRAME.
I managed to have both installations side by side: the only care, obviously, is to install them in different folders. I also uncheked the "Install VST Plugins" during the setup of 4686, installed after the 4881.
Of course, you can't have both of them running simultaneously, but this doesn't affect at all the workaround.
And now, the procedure:
1. Open the VE Pro Server 4686.
2. Add a new instance assigning to it a name
3. Switch on the Audio Engine of the instance you are configuring (IMPORTANT!!!)
4. Add the instance of Play and configure it, loading all the instruments you need (you can repeat this step as many times as you need)
5. Save your VIFRAME and close it
6. Exit the VE Pro Server 4686
7. Open the VE Pro Server 4881
8. Open the METAFRAME where you want to integrate the new VIFRAME
9. Add a new instance
10. Load the VIFRAME you have previously saved using the 4686 Frame editor
11. Close the Frame Window
12. Save the METAFRAME (you can save it with a new name just to be sure not to lose your previous configuration)
It worked like a charme for me.
Best,
Luigi.