trying to convert NGDC HYD93 format data (b93) to ascii text xyz or csv.

 

using CSV as the target format, i'm using coordinateextractor to expose the xyz values. the problem is, the z value is being converted to a positive value, while it is negative in the original data. I've been plaing with paramaters in both the coordinate extractor, the target writer featrue type, nothing. any thoughts, either preserving the negative value, or multiplyiing the attribute by -1 by a paamater in the writer, or an arithmatic operator for the writer value?