How to handle events from Usercontrol in separate AppDomain

Question

I have a number of dll assemblies with usercontrols that I load into a Border control in my main window (like old MDI approach). I wish to now load these assemblies into a separate AppDomain. I have been unable to get events raised in the usercontrols to be received by the parent AppDomain.

What I currently have (working well)

Dim CurrentAssembly As Assembly = Reflection.Assembly.Load("SimpleAss")
MenuFeatureUC = CurrentAssembly.GetType("SimpleNS.UserControl1")
Dim CurrentInstance As FrameworkElement = Activator.CreateInstance(MenuFeatureUC)
ContentHostBrDr.Child = CurrentInstance

The event handlers, that the UserContrtols can raise to –for example-disable buttons in the parent window, are like:

Dim Events = CurrentInstance.GetType().GetEvents()
Dim DisableHandlerMethod = Me.GetType().GetMethod("DisableHandler")
For Each ev In Events   
  If ev.Name = "DisableMethodInParent" Then`
    ev.AddEventHandler(obj, [Delegate].CreateDelegate(ev.EventHandlerType, Me, DisableHandlerMethod))
  End If
Next

Public Sub DisableHandler(ByVal sender As Object, ByVal e As EventArgs)
    MainWindowButton.IsEnabled=false
End Sub

The UserControls raise these events as required.

Public Class UserControl1
Public Event DisableMethodInParent As EventHandler

Private Sub RaiseDisableEventBut_Click(sender As Object, e As RoutedEventArgs) Handles RaiseDisableEventBut.Click
        RaiseEvent DisableMethodInParent(Me, EventArgs.Empty)
End Sub
End Class

What I CAN do I can load the Usercontrols into a separate AppDomain using this code. It works well.

Dim domaininfo As New AppDomainSetup()
domaininfo.ApplicationBase = System.Environment.CurrentDirectory
Dim adevidence As Evidence = AppDomain.CurrentDomain.Evidence
SeparateAppDomain = AppDomain.CreateDomain("SeparateDomain", adevidence, domaininfo)
Dim ProxyType As Type = GetType(Proxy)
ProxyInst = DirectCast(SeparateAppDomain.CreateInstanceAndUnwrap( ProxyType.Assembly.FullName, ProxyType.FullName), Proxy)
ProxyInst.InitDomainWPFPlugin("SimpleAss", "SimpleNS.UserControl1")
Dim contract = DirectCast(SeparateAppDomain.GetData(SlotName), INativeHandleContract)
Dim control = FrameworkElementAdapters.ContractToViewAdapter(contract)
ContentHostBrDr.Child = control

...

Public Class Proxy
Inherits MarshalByRefObject

Public Sub InitDomainWPFPlugin(ByVal AssemblyName As String, ByVal TypeName As String)
  Dim WPFControl As Control = DirectCast( AppDomain.CurrentDomain.CreateInstanceAndUnwrap( AssemblyName, TypeName), Control)
  Dim host = New Border With {.Child = WPFControl}
  Dim contract = FrameworkElementAdapters.ViewToContractAdapter(host)
AppDomain.CurrentDomain.SetData(SlotName, contract)
End Sub
End Class

What I CANT do I have been unable to get the event handling to work across the AppDomain boundary. Most examples on this require Inherits MarshalByRefObject Which a Usercontrol cant do. Examples I’ve come across about wrappers were not close enough to my scenario, or too complex for me to follow. I would be grateful for any assistance on what is required to make the events work.