At the RTL website there's nothing mentioned about a live stream (but also nothing about their TV coverage, so maybe they put this next week on their website).
Maybe they put a link on their website so keep an eye on these websites:
http://www.rtl.nl/sport/rtl_gp/lemans/home
http://www.rtl.nl/sport/rtl_gp/rtlgp
Maybe there's some coverage on
http://tv.audi.com