I personally use this to drag values from the custom area with several values:

<?php  $mykey_values = get_post_custom_values('services');
    foreach ( $mykey_values as $key => $value ) {
    echo "<li> $value</li>";
    } ?>

I wish to sort the output based on the way I've setup the values within the key (alphabetically)

Perhaps you have checked out this?

$mykey_values = get_post_custom_values('services');
sort($mykey_values, SORT_STRING);
echo "<ul>\n<li>" . implode('</li><li>', $mykey_values) . "</li>\n</ul>";

Documentation for [cde] and [cde].