You have AA and AF set to use application settings. Try setting those to disabled and see what happens.

The funny thing is this: there isn't a "disabled" status at all.. the best thing is "use application settings" :/ (the other 2 available options are override application settings and enhance application settings)
If someone knows how to really disable it I would gladly hear that

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Sure. Open SkyrimPrefs.ini and find a line that says 'iMultiSample=x' - if x is something else than 0, hardware antialiasing is enabled.

If need to change x to 0, remember to set the file read-only afterwards.

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It was already at 0, I tried to set it read-only but it's still the same ad before

EDIT: sorry I wrote something wrong about AA, nevermind.
I already had iMultisample=0 and didn't change anything (if I have iMS=2 or more the ENB warning appears btw and I can't use ambient occlusion at all), the problem is not on the whole ambient occlusion feature but it's limited to SSIL..

Update 28/2/2013: I tried even the injector but nothing, there is no SSIL in my game.

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PC INFOS:
Win 7 64-bit // Gigabyte nVidia GeForce GTX 770 OC GV-N770OC-4GD Core 1137 1189MHz // CPU Intel Core i5-3550 3,3GHz // G.Skill Ripjaws 8GBXL 1333MHz

Ok, I don't know how and why but now SSIL works O.O
I did some accurate tests here and there with many others configurations and now everything seems in place.
EDIT [IMPORTANT]: ok I found out, I don't know if it's like this for everyone but basically I always started the game with ambientocclusion=false, because I activate it with DoF/SSAO toggler only when taking screenshots, this time I started the game with ambientocclusion=true and SSIL magically works.
That's a bug I suppose..?

Sorry to have bothered you, if I found out why now ssil works I will report it.. who know that maybe I changed something and I didn't noticed.

Thank you all for the efforts

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PC INFOS:
Win 7 64-bit // Gigabyte nVidia GeForce GTX 770 OC GV-N770OC-4GD Core 1137 1189MHz // CPU Intel Core i5-3550 3,3GHz // G.Skill Ripjaws 8GBXL 1333MHz