Firing business rules on property changed for a private backing field

We are just upgrading from an older version of CSLA to the new framework (4.5.6) and having a little difficulty with one scenario.

I have a CSLA class (Model) referencing properties on another CSLA class (Relation) as a private backing field. The registration is setup like this:

Public Shared ReadOnly ReferenceProperty As PropertyInfo(Of ReferenceType) = RegisterProperty(Of ReferenceType)(Function(c) c.ReferenceType, "Reference Type", RelationshipTypes.PrivateField)
        Public Property ReferenceType() As ReferenceType
            Get
                Return GetProperty(ReferenceProperty,_reference.ReferenceType)
            End Get
            Set(ByVal value As ReferenceType)
                SetProperty(ReferenceProperty,_reference.ReferenceType,value)
            End Set
        End Property

The "Model" montors for changes to the property in "Relation" and fires OnPropertyChanged("string name of property") on itself to fire the business rules on itself in case it's changed elsewhere. The property in Relation and the property in Model have the same string name:

Private Sub ReferencePropertyChanged(ByVal sender As Object, ByVal e As PropertyChangedEventArgs) Handles _reference.PropertyChanged
            If Me.GetType.GetMembers.Select(Function(m) m.Name).Contains(e.PropertyName) Then
                OnPropertyChanged(e.PropertyName)
            End If
        End Sub

The problem is that firing this OnPropertyChanged doesn't fire the business rules tied to the Model property any more. I can fire the business rule manually by adding a little more reflection and that works fine:

Dim prop As IPropertyInfo = FindProperty(e.PropertyName)
If prop IsNot Nothing Then
         BusinessRules.CheckRules(prop)
End If

Whenever I need to use reflection though I run under the assumption I must be doing something wrong. Is there something extra I need to do to have validation rules fire OnPropertyChanged for private backing fields?