After struggling for quite a while, my connexion works today. For what it is worth and if that may help a fellow simmer, I realised that the simconnect.xml was somewhat corrupted when I tried and couldn't open it with the xml editor while it was perfectly readable with the Notepad with what I had initially written it. Rewriting the few same lines in a new xml did the trick. Using P3D with W7 and IPV6.