How do I add buttons to the tinymce editor when used on case description?

Hi I have amended the description field on a case so it supports HTML and the tinymce editor via adding the file \custom\Extension\modules\Cases\Ext\Vardefs\sym_descript_rich.php

<?PHP
$dictionary['Case']['fields']['description']['type'] = 'htmleditable_tinymce';
$dictionary['Case']['fields']['description']['dbType'] = 'longtext';

shot of descript field in cases


This works nicely but would be better if it had some of the same characteristics as the description box in the Knowledgebase article - namely
1. Larger Field height - ideally resizable (works the same way as the KB
2. the Button for inserting a hyperlink
3. the toolbar button for inserting a picture.

4. A "nice to have" would be the Clear formatting button.

Descript box in KB

Any help would be welcome.

Regards

Greg Mackey