Currently it is not possible to show more than 1 column with a descriptionproperty.This makes it very hard to identify types that have a uniqueness over more than one column.Using some sort of concatenation or even a query (SQL) or calculated field might be more of value.As an extra; it might be handy to tell that a field is part of the descriptionproperty while declaring the type in "M".
What distribution are you using?