As I understand, your camber goes more negative when you compress the suspension?
If so, check that the upper link is sloping from the tire side DOWN towards the chassis or is at least parallel to the lower arm. I think your proble is a result of the upper arm actually sloping down from the chassis outside towards the tires. You don't have a roll center to speak off.
Also when trying to simulate cornering "do the twist" suggested above
or push down the "outside side" AND also simulate the centrifugal force by pushing the car by its side towards the "outer side" of the corner. You'll also have to apply more force on the rear end of the car to simulate cornering out on power, and apply more force on the front end to simulate entering a corner off-power.
You will notice that you would seem to be trying to force the tire from (leaning towards the chassis) to (leaning away from the chassis, resulting into positive camber). If you find that you are in fact decreasing the camber (the tire leans more towards the chassis) , try moving the chassis-side end of the upper arm DOWNWARDS until the (upper andlower arms are parallel) or (the inner end of the upper arm is lower compired to the tire-side end)
Sorry if I made it more confusing. I'm basically trying to explain some of the posts above.