Short game with slope "upward"

[lamonpa]

Hi Bobby,
In your DVDs "Pitching" and "Short game" you mention that we should have at least 70% of our weight on the left foot. It goes's perfectly with flat lies but the problem is that the lies near the greens have quite often a big slope "upward". I tried your suggestion "Golf Ball in the middle/shoulders parallel to slope..." but I got problem (stance!)with the "70% of the weight on the left foot". The result is very inconsistent.
Could you please give me the way I can manage this case?
Thank's a lot.
Paul-Henri