This is a bug... the only hastes that are effectively reducing ability cooldowns are the ones titled 'haste'. the rogue epic haste is granting you auto attack haste equivalent to its value but it will not affect ability cooldowns because it is titled 'Seething Fury'.
This is a known issue and is currently being discussed in bugs:
http://www.project1999.com/forums/sh...d.php?t=251700
http://www.project1999.com/forums/sh...=240866&page=8
maybe some of you guys can check it out and contribute to some data collection.