Colin,

 

ExecCommand doesn't support any custom button. All the support commands can be found in http://cutesoft.net/developer+guide/index.html.

 

For your questions, I suggest you create a custom button. When the user click this button, you can call you own javaScript then post back the form.

 

For example:

 

<script>

   function MyCustomButton ()

  {
          //run your own script here.
          alert("Hello");

            // get the cute editor instance        

         var editor1 = document.getElementById('<%=Editor1.ClientID%>');

         editor1.ExecCommand("PostBack");
   
  }

 

</script>