According to the WordPress Codex 1, it is possible to pass quotation marks via the parameters of the function,
wp_link_pages(). This would enable users to assign a particular css
id to the function output, thereby providing greater design and behavioral control over that particular object.
But alas, as reported several times in the WordPress Codex 2,
wp_link_pages() is unable to pass quotes without causing errors.
To fix this, we open
template-functions-post.php and find
wp_link_pages(), which is located around line #121 (for WP 2.0.2).
The fix is easy, simply edit the
p> in the following lines:
$r['before'] = '<p>' . __('Pages:');
$r['after'] = '</p>';
For example, if you wanted to wrap the function output with a
div class="foo"> and subsequent
$r['before'] = '<div class="foo">' . __('Pages:');
$r['after'] = '</div>';
Upload and done. Do not forget to eliminate the
after= parameters when calling the function from the loop 3.