Problems to login via POST on a external site.

Hallo, I know that this is a little bit of topic but I don't know any better place to post my Problem. I want to automatically POST values to the site: http://clever-tanken.de , a german site to view fuleprices of gas stations in your area. I watched the traffic I captured with wireshark an found two POST values that I can't find in the HTML code. The POST values are x=<some number from 0-99> and y=<some number from 0-99>. You can find the <form>block here: http://pastebin.ca/raw/255964 It is the start site where you can login to change your data. The traffic shows: user=seppl2&pass=seppl2&x=72&y=13 but I don't know where the x and y values are from. They also change every time. The full HTML you can find here: http://pastebin.ca/255968 or just log on to http://clever-tanken.de Maybe someone will find the Time to help me. You can log in with: user=seppl2 passwd=seppl2 Thanks Ben -- "Ein Herz für Kinder" - Ihre Spende hilft! Aktion: www.deutschlandsegelt.de Unser Dankeschön: Ihr Name auf dem Segel der 1. deutschen America's Cup-Yacht!