For plugin: Hiding own divs in Write Post admin panel

Hi, WP 2.0 has a new feature displaying a +/- at the right side of any caption like “Optional Excerpts”, “Trackbacks”, etc. in the “Write Post” admin panel, causing the division to expand/collapse when pressed.

For a new plugin I already used the filter/action “simple_edit_form” and “edit_form_advanced” to display my own additional div, but haven’t found out how to add these expand/collapse functionality.

What do I have to do to let my divs behave the same way as the original WP ones?.