For the server side controls, please check the following article:

 

How to create a custom button (Server Control) and register it with the editor toolbar template?

 

http://cutesoft.net/example/howto/RegisterServerControl/vb/RegisterServerControl.aspx 

 

Example code:

 

        Dim hello As New System.Web.UI.WebControls.Button
        hello.Text = "Hello"
        hello.Style("vertical-align") = "middle"
        hello.CommandName = "Hello"
        AddHandler hello.Click, AddressOf hello_Click

        Dim world As New System.Web.UI.WebControls.Button
        world.Text = "Hello"
        world.Style("vertical-align") = "middle"
        world.CommandName = "world"
        AddHandler hello.Click, AddressOf world_Click

        Editor1.RegisterCustomButton("hello", hello)
        Editor1.RegisterCustomButton("world", world)