The transfer of raw data from a source data structure to a target data structure that represent the same item. During the data transfer, if there is a given field in the target data structure that does not correspond to a field supplied by the source data structure, the transfer mechanism determines whether or not it is mandatory that the source data structure supply the field. If it is mandatory, the transfer fails. Otherwise, the transfer continues. If there is field of the source data structure that does not correspond to a field of the target data structure, the transfer mechanism determines whether or not it is mandatory that the target data structure have the field. If it is mandatory, the transfer fails. Otherwise, the corresponding data may be provided to a residual field of the target data structure dedicated for unknown data.