I have a map package file which specifies the symbology and labels for my FeatureLayer. I can create and display labels from any attribute EXCEPT Shape_Length or Shape_Area and the labels will display in my application. Labels using Shape_Length or Shape_Area attributes will display only in ArcMap. I've tried this with several different attributes. The FeatureLayer's Labeling property has the same properties each time (except for the TextExpression field, which is "[Shape_Length]" or "[some_other_fieldname]"). How do I display labels which use Shape_Length or Shape_Area?