We have a requirement that the Message Control Id (MSH.10) of the HL7 ACK message should be equal to the message control id (MSH.10) of the original message. We are using BTAHL7 with BizTalk 2013 R2, CU5. In our case at present, the message control id of ACK is actually a permutation of the original message's message control id. Any help would be appreciated.
The correct answer: don't even try. This is not standard HL7.
The ref value is in MSA02 per HL7.
This is not a problem with HL7 or BizTalk Server. This is a problem created by your Trading Partner.
If this is being pushed by a Trading Partner, the first response is simply NO, because this is not standard HL7.
If they keep pushing this, your next step is to inform your management that because the Trading Partner is requiring non standard HL7, it will take you a lot of extra time and money to support this. You will need a completely custom numbering scheme.