help for Gambit: 2 edges + 1 boundary layer
 

I encountered a difficulty with Gambit that I can not solve after several day's trial.

In a rectangular virtual face I built a boundary layer (altogether M layers, lets say M=10) at the bottom virtual edge. That's O.K. Then whenever I tried to mesh the two vertical virtual edges in to N (N>M, lets say N = 20) equal space parts, the left vertical edge will include the boundary layer into its meshing scheme so it will have 10 meshing withing boundary layer and another 10 meshing beyond boundary layer, but the right vertical edge will not do like this, it is BLIND to the boundary at all so it has totally 20 exactly equal meshing. In this way, a distorted quadrilateral meshing was produced.

Hope to get experts' opinion. Thanks.