Thanks a lot everybody.
Tried opening port 62716 on my router, but still no way.
I was hoping PR1.3 would fix it, but it doesn't.
Actually, I'm right where I was before.
After I flashed PR1.3 with NSU, first disappointment came with Firefox 13 from Ovistore. It downloaded fully, but install failed. Toggled 3G, retried and there it was. Since then I didn't activate dev-mode, only installed some apps from Ovistore directly.
For now I blame my router for the WIFI-unability. Will try to get a new one from my provider.
@chemist: Feel free to merge with this one. Thanks.
N9 64GB BLACK PR1.3 (40.2012.21-3_PR_001)