Superfilling only inside the trench

I need to modify the COMSOL 4.3 "Superfilling" verification model (provided in the Electrodeposition examples), in such a way as to consider only the inside walls (two vertical and one horizontal in the 2D representation) of the trench as "Depositing boundary".
According to this new situation, point 1 can't be chosen as eligible point for the integration step (intop1).
How could I modify the model to obtain convergence?
Thanks in advance.