Hi Stefdv
The code that Thomas added works fine, the problem in my site wound up being that I had two forms (one hidden) where the text area field had the same name and therefore the same ID, which then made the javascript unable to work correctly as there was not a unique ID.
So based on Thomas' code below you need to create a file in the mysite/code folder called 'FrontendHtmlEditorField.php' and then whatever page you are using it on the form would be something like...
public function MyForm(){
$contentfield = new FrontendHtmlEditorField('Content', _t("ContentEntry.CN",'Content'));
$fields = new FieldList(
//your other fields
$contentfield
);
$actions = new FieldList(
new FormAction('submitForm', 'Submit')
);
$form = new Form($this, 'MyForm', $fields, $actions);
return $form;
}
Then you would have your 'submitForm' function for processing the form and in the template you would just have $MyForm wherever you want the form to appear.