How to debug Outbound IDOC

In some cases investigation with IDOC is very difficult  outbound process.
Example : Modification of Segment Data.,

There are steps to check this process.
1. Check function module in SM37  with name of message type example '*ORDSP*'.
2. Check Segment Where used list in SE11 transaction.
3. Always used Update debugging because normally IDOC are process in Update Task.
4. Normally funcation module used to process IDOC will have routine to fill segment. Better to search routine in function module to put break point.