Custom RoutedEvent Issue

I have a hierarchical structure of UserControls that I need to have a custom RoutedEvent to work with. What I need is to be able to have a parameter bubble through the hierarchy of controls with certain controls modifying the parameter so that when the event bubbles up to the base of the hierarchy I have a URI-like parameter that describes the path it took.

So far I have created a class derived from RoutedEventArgs that adds a String parameter to the event argument.

Public Class ShowAsEventArgs
        Inherits RoutedEventArgs
        '
        Public Sub New(ByVal evt As RoutedEvent, ByVal myName As String)
            MyBase.New(evt)
            mFieldPath = myName
        End Sub
        '
        Private mFieldPath As String
        '
        Public Property FieldPath As String
            Get
                Return mFieldPath
            End Get
            Set(value As String)
                mFieldPath = value
            End Set
        End Property
    End Class

I have also defined the routed event in the "BitField" class:

    Public Shared ReadOnly ShowAsFieldEvent As RoutedEvent = EventManager.RegisterRoutedEvent("ShowAsField", RoutingStrategy.Bubble, GetType(RoutedEventHandler), GetType(BitField))
    '
    Public Custom Event ShowAsField As RoutedEventHandler
        AddHandler(value As RoutedEventHandler)
            Me.AddHandler(ShowAsFieldEvent, value)
        End AddHandler

        RemoveHandler(value As RoutedEventHandler)
            Me.RemoveHandler(ShowAsFieldEvent, value)
        End RemoveHandler

        RaiseEvent(sender As Object, e As BitField.ShowAsEventArgs)
            Me.RaiseEvent(e)
        End RaiseEvent
    End Event

The problem I am having is adding a handler for this event, I tried this in my "Peripheral" class:

 AddHandler BitField.ShowAsFieldEvent, AddressOf HandleShowAsFieldEvent

However, I get an error that says that "ShowAsFieldEvent" is not an event of "BitField". 

I spite of lots of searches I am unable to find an example of how to do this. Any input would be much appreciated.
Sid.