Using Tracking code behind a proxy server (no replies)

Hi,

I have installed a piwik server in my company in order to analyse user traffic on all our websites.

For these websites, I have to use the tracking code :

<script type="text/javascript">
var _paq = _paq || [];
_paq.push(['trackPageView']);
_paq.push(['enableLinkTracking']);
(function() {
var u="//URLTOPIWIK/piwik/";
_paq.push(['setTrackerUrl', u+'piwik.php']);
_paq.push(['setSiteId', 2]);
var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
g.type='text/javascript'; g.async=true; g.defer=true; g.src=u+'piwik.js'; s.parentNode.insertBefore(g,s);
})();
</script>
<noscript><p><img src="//URLTOPIWIK/piwik/piwik.php?idsite=2" style="border:0;" alt="" /></p></noscript>

The problem is that URLTOPIWIK is only reachable through an internal proxy for each of my web servers to analyse, let say
PROXY URL : proxy-internal.local
PROXY PORT : 8080

How could I change the tracking code to use an internal proxy please ?

Thans for your help !

Loki