I've created a custom module that defines a menu callback; that menu path will call a function which performs some actions and once it's finished, it needs to display the theme with a message as the body.
This used to be doable using
theme('page', $message) but in Drupal 7 it only returns the HTML content that would normally appear within the BODY tags.
I know that there is now a
html.tpl template, but I'm unsure how I can combine the two to generate a full page.