Plugins for windows Phone 8.1 doesn't work. Mono compiler errors

I am having problems when I try to develop plugins for WP 8.1 I build my fake dll and WP 8.1 class library. When I put my real plugin to
Assets\Plugins\WP81 I am getting this error:

Error 1 Internal compiler error. See the console log for more information. output was:
Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly ‘System.Runtime, Version=4.0.10.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’ or one of its dependencies.
File name: ‘System.Runtime, Version=4.0.10.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’
at (wrapper managed-to-native) System.Reflection.Assembly:InternalGetType (System.Reflection.Module,string,bool,bool)
at System.Reflection.Assembly.GetType (System.String name, Boolean throwOnError, Boolean ignoreCase) [0x00000] in :0
at System.Reflection.Assembly.GetType (System.String name) [0x00000] in :0
at Mono.CSharp.RootNamespace.GetTypeInAssembly (System.Reflection.Assembly assembly, System.String name) [0x00000] in :0

It works for WP 8.0 though. Is WP 8.1 plugins not supported, has anyone tried ?

That actually a good question.
I can’t answer it now, but WP 8.1 is part of WSA, can you try to put your plugin under plugins/metro ?

Hi,

you’re putting them in a wrong directory. Probably it’s our fault for having bad docs - I’ll make sure it’s fixed. Check this:

http://docs.unity3d.com/Manual/WindowsUniversalApps-faq.html

You’re supposed to put them here: “Assets\Plugins\Metro\WindowsPhone81”

Furthermore, if your plugin doesn’t use explicit phone features which are not available on Windows Store (like vibration device), you can just build one plugin for Windows Store Apps and it will work fine for Windows Phone 8.1 (in that case, put it to Assets/Plugins/Metro).

Yay it worked. I put them under Metro. I should have read the docs more thoroughly.
Thank you.