It seems that as soon as you mark a page as "private" it disappears from the
wp_list_pages() output even though I am logged in as the admin and created the page in question with the same account. I tried it on a fresh WordPress 2.2.1 install with the default theme and it confirms my finding.
I do not believe this should be the correct behaviour as the post behave as expected.
I did try the many different access restriction plugins out there but they either do not work well with WordPress 2.2.1, or conflict with other plugins (Event Calendar 3 or ical4wp for instance)
I could not find a trace of this behaviour anywhere in the forums or in the bug database. Can anyone replicate my finding? As anyone found a workaround? I certainly could hard code the link to the pages but the function is really much more elegant and flexible and using the private pages is the best solution for my purpose and insure the best forward compatibility.