First, SW Duration Exterior has a lifetime limited guarantee which requires the use of primer on certain surfaces, treated lumber included. Also, Duration Exterior requires the use of 2 coats for the guarantee - look at the fine print, it is supposed to *hide* and *protect* in one coat (the first coat acts like primer on certain surfaces), but two coats are required. Also, the guarantee does not replace the cost of labor or paint, it just gets you some new gallons of the same stuff *if* the SW laboratory believes that paint failure was the cause of your trouble. They most certainly will not if you paint treated lumber with one coat and no primer.
Treated lumber is pressurized with the treating liquid, so over time it will leech the liquid to kill termites, protect the wood, etc. This is designed to last for several months to years. If you coat the wood with paint, the treating liquid will continue to leech out underneath the paint, eventually destroying the paint binder and making the paint peel right off. The same thing happens to unprimed cedar and redwood which have tannins - a resin that is leeched out of the wood which destroys coatings.
Your best bet is to leave the wood in the sun for several months until it no longer leeches liquid, and then coat. It is designed to look good for a long time, so unless you can't deal with the color just leave it. Otherwise, try coating it in an *oil* based exterior primer. Oil will try to penetrate the wood, so if there is any room left in the wood pores to make the primer stick, then it will. Otherwise, the primer will peel right off. When you can get primer to stick, you can topcoat in Duration (and since you got primer to stick, you can use 2 coats for your warranty). Personally though, I'd rather use A-100 at $30 per gallon than Duration at $60 per gallon considering the risk.
Also, is this a walking surface? If so, then rethink everything - using a standard latex, even as good as Duration Exterior, will cause you grief. Look into SW Porch and Floor Enamel (only if you can get oil primer to stick, however).