Off the top of my head, I think what you should do is put all of the functions into a single file. Then in the custom island you'd do something like:

PHP Code

require("/home/sparky3/etc/phpwebcounter/phpwebcounter.config.php");
require("/path/to/functions/file.php");

hits_webcounter($webcounter_id,$path_hits_file,$visible,$path_images,$counter_pad, $step);

if ($banner == '1') {
$body = <<<EOF
<br><a href="http://phpwebcounter.sourceforge.net"><font size=1px>PHP Web Counter</a></font size><br>
EOF;
}