No such luck to get SSI Web to automatically manage this custom type of data as suggested by Wirth. You'll want to follow Ralph's recommendations, and also look at the paper by Horne also in the 2012 Proceedings for ideas regarding the coding. Then, you'll want to directly prepare your data in the .csv format and submit it directly to CBC/HB for parameter estimation. This will require knowledge of how to dummy-code design matrices.
If you get stuck with all this, we do have a consulting group (Sawtooth Analytics) that is willing to do such efforts for a fee.