Patience my webassist friend, i also struggle a lot with webassists's wysiwyg products because it use FCKEditor.. so you have to understand the nature of FCKEditor as well.
it took me almost one week to 'master' iRite.. the same problem happen on HTML Editor as well.. but when you master it, the 'preset' feature will save a lot of your development time in the future.
Regarding your problem, the cache problem arise in HTMLEditor/editor/fckeditor.html
you can erase (or i prefer commented) the line 29 :
<meta http-equiv="Cache-Control" content="public">
you can enable it on public/production server when your project goes life...