XML error – Missing elements in possible ALL group

We have just upgraded to 5.7 and are receiving errors that were not found in 5.5.   The error is “Missing elements in possible All Group at nm1.micro_result.nm1:resultes.0(0).   Please review the schema definition and populate the required nodes if necessary”.  

In reviewing the xlate, we have determined that a required field in the schema is not populated because the inbound message does not contain it (we are converting HL7 to XML outbound).   In redefining the schema to minOccurs=”0″, the recompile work but we are still seeing the error.   The message does appear to process outbound but we can’t stop the error from occuring.    How can we remove the error when processing these messages?