Wpf 绑定到代码隐藏中定义的自定义控件属性

我在代码隐藏中定义了一个自定义控件：

Public Class MyControl
    Inherits Button
    Private _A As String
    Private _B As String

    Public Property A() As String
        Get
            Return A
        End Get
        Set(ByVal value As String)
            _A = value
        End Set
    End Property
    Public Property B() As String
        Get
            Return B
        End Get
        Set(ByVal value As String)
            B = value
        End Set
    End Property    
End Class

下面是标记：

<ControlTemplate TargetType="{x:Type local:MyControl}">
      <StackPanel>
         <TextBlock Text="{Binding ?????}"/> <!-- A Property -->
         <TextBlock Text="{Binding ?????}"/> <!-- B Property -->
       </StackPanel>
</ControlTemplate>

我必须编写什么代码来绑定这些属性

{Binding Path=A, RelativeSource={RelativeSource AncestorType={x:Type MyControl}}}