Trigger inbound BAPI IDOC for message type ACC_GL_POSTING

Refer to function group EDIN.

- Use EDI_DATA_INCOMING if you want to pass a IDOC file.
- Use IDOC_INBOUND_SINGLE or IDOC_INBOUND_ASYNCHRONOUS if you want to pass IDOCs in memory.

Additional information can be found in the book "ALE, EDI, & IDoc Technologies for SAP" pages: 99, 207, 262, 498.