def columns_to_hash(valid_columns, columns, keys_case=:underscore)
			raise Exception.new("Invalid time value: nil") if columns.nil?
			
			key = self.class.to_s.demodulize.gsub(/ReportRequest/, 'ReportColumn')
			return { key => 
					columns.map do |col|
						if col.is_a?(String)
							col
						elsif col.is_a?(Symbol)
							valid_columns[col.to_s]
						end
					end
				}
		end
def columns_to_hash(valid_columns, columns, keys_case=:underscore)
			raise Exception.new("Invalid time value: nil") if columns.nil?
			
			key = self.class.to_s.demodulize.gsub(/ReportRequest/, 'ReportColumn')
			return { key => 
					columns.map do |col|
						if col.is_a?(String)
							col
						elsif col.is_a?(Symbol)
							valid_columns[col.to_s]
						end
					end
				}
		end
Public : Return the columns attribute of the ReportRequest as a valid Hash for SOAP requests

 Author:: jlopezn@neonline.cl

 keys_case - specifies the keys_case for the hash: :underscore or :camelcase

 Returns:: Hash