Rosettanet Business Message Identification in custom receive

We are having a custom receive flowservice.
All the trading partners submit the documents to the custom receive service.
This does some pre processing and then resubmits the document to TN for firing a process model.

when the custom receive service resubmits the data to tn.receive and the TN db
is down we store the data in a MQ and resubmit later.
This is achieved for all kinds of documents except rosettenet 3A4 document.

Can any one help in the following issues…

Question 1)
With Rosettenet business message, can anyone tell me the variable name through which the content is submitted. For instance in EDI we have “edidata” .

Question 2)
Rosettenet business message has multiple contentpart like service header,preamble,content etc.How do I store the multiple data as a single message in MQ such that when the MQ data is dequeued and re-submitted to rn.receive it should fire the rosettenet PIP model.

Please help. Any pointers is welcome

Srinath S Rao