What you want to achieve:

 

When the editor loads, you want the text in the editor pick the style from the "normal" class instead of the default normal paragraph style. Is that correct?

Try create separate css file:

body, td
{
   /* copy the content from your normal csss here */
    font:normal 11px verdana;
}

EditorWysiwygModeCss = s1 & "," & s2 & "," & s3 & ", " & s4 & ",mystyles.css"

Hope it helps.

 

Please note that the editor doesn't have the ability to automatically apply class whenever the user type.