Ok, so guys you might say this user is retarded but somehow I've did it.
It is really important to press both buttons in very same time, snapshot will be ther in like 2 seconds...
What is happening with people with only one hand? I am not joking.. This ICS update for taking a screenshoot, I find very awkward and not friendly too..
Thank you guys once again, now I am able to take some screens.. I needed in the first place for my friend to show him that WiFi is working more than fine on my Arc S and I do not experience any breakups with WiFi connection.
As far as good for now. All stock.