Due to a bug I introduced a few versions ago, private pages can only be listed in your site’s sidebar / topbar if Role Scoper’s hidden content teaser is enabled. To make private pages listable for users with a sufficient role, please perform the following officially sanctioned Role Scoper hack:

In wp-content/plugins/role-scoper/hardway/hardway_rs.php, add
if ( $list_private_pages ) $request = str_replace("AND post_status='publish'", "AND ( post_status IN ('publish','private') )", $request);
just before

if ( ( ! is_admin() && ! defined('XMLRPC_REQUEST')
As you know may know, this functionality also requires enabling the checkbox “include Private Pages in listing if user can read them” in Role Scoper Options.

An equivalent fix will be included in the next Role Scoper revision.