"After getting to the place, get into the parked car and wait for Popstar. When he enters his car, you have to follow him. Try not to get to close to him, don't honk and destroy other cars, because you'll fulfill the suspicion bar and you'll have to start all over again.
A moment later you get an order to photo trading bandits. Take out phone, press L2 and then press R1 to make a photo.
Next photo you have to make from the ground in the moment you get such an order. When you finish, wait until half of enemies go away and follow Popstar.
To pass the guard in the port, do the Fast Talk (press triangle in the particular moment).
Later you have to climb up on the pointed boat, to make a photo of the gangster after the first shot.
When you finish, return to the van and take it to the marked garage. Police will start chasing you, but you shouldn't have problems with losing them (remember to use square). When you call Teng, the mission ends.