MimmiN on "Html editor in form in plugin"

I'm building a local plugin to edit my custom tables, using forms. I would like to be able to use the WP html editor when editing text areas of the form. That is, I want the admin of the site to use the WYSIWYG editor in order to create links etc, and that the text being put into my table is html-code.

How may I achieve this?

I saw this post:
http://wordpress.org/support/topic/convert-text-area-into-wp-editor

So I'm able to put the editor there, but how do I define what row of the table to update with this instead of a normal text area?

In my mysql_query I define:
$beskrivelse = $row['beskrivelse'];
In my form I have:
<p><label>Beskrivelse av kurset </label><textarea name="beskrivelse" cols="90" rows="4"><?php echo $beskrivelse?></textarea></p>