Don't let him out to poop off leash yet. Every time he needs to go out, he's got to be leashed, and walk him around the perimiter of HIS yard and let him mark HIS territory. Don't let him past where you want him to think is HIS.

Establishing territory boundaries is part of training a new dog. It's easier when the breed is already territorial- my old Boxer x was VERY easy and it only took a couple weeks of leashed pooping before she figured it out. Same goes for the road- it's NOT his territory and you should scold him if he tries to go into the street without YOUR permission.