How to track visitors to two different idSite?! (Code not work!!) (no replies)

Hello,
I am developing an application and I need to log the visitor in two different idSite.

I have read the code

 window.piwikAsyncInit = function () {
...
}

, but I can not make it work.

The following code, Premise that by tracking in a single instance works correctly.

<script type="text/javascript">
window.piwikAsyncInit = function () {
			try {
				var u=(("https:" == document.location.protocol) ? "https" : "http") + "://traffico-visite.eu/ns/5/";
				
				var piwikTracker = Piwik.getTracker(u+"piwik.php", 17);
				piwikTracker.appendToTrackingUrl('new_visit=1');
				piwikTracker.deleteCookies();
				piwikTracker.setReferrerUrl( 'http://www.mive.it' );
				
				piwikTracker.trackPageView();
				
				var piwikTracker2 = Piwik.getTracker(u+"piwik.php", 9);
				piwikTracker2.appendToTrackingUrl('new_visit=1');
				piwikTracker2.deleteCookies();
				piwikTracker2.setReferrerUrl( 'http://www.mive.it' );
				
				piwikTracker2.trackPageView();
				
			} catch( err ) {
				alert('Errore');
			}
		};	

  (function() {
	var u=(("https:" == document.location.protocol) ? "https" : "http") + "://traffico-visite.eu/ns/5/";
	var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; g.type='text/javascript';
	g.defer=true; g.async=true; g.src=u+'piwik.js'; s.parentNode.insertBefore(g,s);
	
	
  })();
</script>