Anbaz,

 

Here is the code to add a custom button.

 void Page_Load(object sender, System.EventArgs e)
 {
    CuteEditor.ToolControl tc = Editor1.ToolControls["insertcustombutonhere"];
    if(tc!=null)
    {    
        System.Web.UI.WebControls.Image Image1 = new System.Web.UI.WebControls.Image ();
        Image1.ToolTip    = "Insert today's date";
        Image1.ImageUrl    = "tools.gif";
        Image1.CssClass    = "CuteEditorButton";
        SetMouseEvents(Image1);
        Image1.Attributes["onclick"]="var d = new Date(); CuteEditor_GetEditor(this).ExecCommand('PasteHTML',false,d.toLocaleDateString())";
        tc.Control.Controls.Add(Image1);
    }
 }

You can just modify the above code to meet your requirements.