First, in SW 2010 surfaces must be inserted in the model because reference geometry cannot be selected when setting up a symmetry fixture. Can't you SW developers do better than that?

So, I insert surfaces, big surfaces for two planes of symmetry that go to the extremities of the model, and I exclude them from the FEA study.  I can select these surfaces to set up the symmetry fixtures.  But when I run the study, the solver reports that the symmetry transfer failed.

So, how does on set up symmetries with shell elements?