you can copy the required files manually, although releasing an app with a Qt Beta version is not recommended. As soon as Qt 5.4 final is out, we will also update all plugins and the V-Play libraries to work with it.
The required files for the Facebook plugin are (for Android):
We only provide dummy files on desktop for the plugins with the V-Play library yet. So if you are using an empty V-Play project .pro file as a template and import the VPlay.plugins.facebook 1.0 in your qml files, it will also work on Windows. We’ll improve this behavior with the next plugin updates.
As another workaround, you can also use a Loader component which includes the Facebook item and Facebook import, and only load it on platforms where you are using the Facebook plugin (most probably iOS & Android).