Confirmed on the Cocoon website...
http://www.cocoon.net/ and
http://www.cocoon.net/popups/underworld/underworld.html
and also detailed on Ibiza spotlight here...
http://www.ibiza-spotlight.com/night...classics_i.htm
I was in Amnesia three weeks ago thinking how amazing it would be if Sven had Underworld there but can't afford another trip out there. Get your pennies together - it will be unbelievably expensive but awesome!