Jlink select sketch dimension

While having a sketch in edition, I want to select and edit the sketch dimension, using Jlink.

I'm using this code for selection.

SelectionOptions selectionOptions= pfcSelect.SelectionOptions_Create("dimension");
selectionOptions.SetMaxNumSels(1);

Selections selections=session.Select(selectionOptions,null);

 But at this moment I'm unable to select the desired dimensions.

Any idea?