Excerpt not working correctly

I’m using a modified version of twentyten, and having an issue with the_excerpt. Here’s the code:

<?php if ( is_archive() || is_search() || is_page('articles') ) : //Only display Excerpts for archives & search ?>
                        <div class="entry-summary"><!-- foo -->
                                <?php the_excerpt( __( 'Continue reading <span class="meta-nav">&rarr;</span>', 'twentyten' ) ); ?>
                        </div><!-- .entry-summary -->
        <?php else : ?>
                        <div class="entry-content">
                                <?php the_content( __( 'Continue&nbsp;reading&nbsp;<span class="meta-nav">&rarr;</span>', 'twentyten' ) ); ?>
                                <?php wp_link_pages( array( 'before' => '<div class="page-link">' . __( 'Pages:', 'twentyten' ), 'after' => '</div>' ) ); ?>
                        </div><!-- .entry-content -->
        <?php endif; ?>

This works great, but when a manual excerpt is used, the “Continue Reading” link disappears. Do I have to manually add this link if I want to use a custom excerpt? It works perfectly with the automatically generated excerpts.