I am trying to use the external image button, but when specified in the template it does not appear.   It only shows when using an autoconfigure statement.  Even in your customize the appearance example, you have it listed in the code:

<CE:Editor Visible="False" id="Editor1" ShowBottomBar="false" Height="180"
      Template="Bold,Italic,Underline,Separator,JustifyLeft,JustifyCenter,JustifyRight,Separator,
      InsertOrderedList,InsertUnorderedList,Separator,Indent,Outdent,Separator,Subscript,Superscript,
      Strikethrough,Separator,Hr,Link,UnLink,Char,Emotion,InsertText,Separator,ImageGallery,ExternalImage,
      Separator,Forward,Backward" runat="server">
</CE:Editor>

Only the image gallery appears, not the external image in the toolbar.  Has the name changed for this button?

Thanks.