Button m_button;
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public Button MyButton
{
    get
    {
        if ( null == m_button )
            m_button = new Button();
        return m_button;
    }
    //set { button1 = value; }
}
public void SetMyButton(Button value)
{
    m_button = value;
}