Fish,
E17 Window manager is not yet offically supported as yet, therefore I would reccomend using e16.7 untill it becomes supported. I can't find anything about installing it with aptitude I think you have to install it Manually
if you want to try to install it, try the Link below
http://www0.get-e.org/E17_User_Guide...pages/2.1.html
remember to do a backup of your files before you start,
Jake