<!-- Inside of slider element -->
<div class="flexslider">
  <ul class="slides">
    ...
  </ul>
  <ul class="custom-controls">
    <li><a href="#">Slide One</a></li>
    ...
  </ul>
</div>

//Inside .flexslider() properties
manualControls: '.custom-controls li a'


<!-- Outside of slider element - must use controlsContainer property -->
<div class"flex-container">
  <div class="flexslider">
    <ul class="slides">
      ...
    </ul>
  </div>
  <ul class="custom-controls">
    <li><a href="#">Slide One</a></li>
    ...
  </ul>
</div>

//Inside .flexslider() properties
manualControls: '.custom-controls li a',
controlsContainer: '.flex-container'