Add dashboard widget to page created with add_menu_page()?

I’ve edited my question to include the fact that I’ve found the answer to my own question here

http://www.code-styling.de/english/how-to-use-wordpress-metaboxes-at-own-plugins

in case anyone finds the question while searching for a similar solution. The two column variation he includes in his solution no longer seems to work but is a simple thing to override.