I am attempting to use setup_postdata as well. It looks like it’s not quite rock solid. I took a more hamhanded approach, and it seems to work ok.
// My new post is stored in $pagepost
$stored_post = clone $GLOBALS['post'];
$GLOBALS['post'] = $pagepost;
setup_postdata($pagepost);
// Now I can use all my functions, including the_title(), etc.
// When I'm done...
$GLOBALS['post'] = clone $stored_post;
No idea why this works, but it just seems that either setup_postdata doesn’t get all the elements in the right place or the other template functions (e.g., the_title(), etc.) seem to ignore what setup_postdata does.
