IDOC Entry in ERP System

Hi experts,

I have a question how to upload IDOC content to ERP system.

We have a customized an IDOC structure which we designed with transaction WE30 and a new message type created with WE81 and WE82.

Filling this IDOC structure and sending it to a different system, we use FM 'MASTER_IDOC_DISTRIBUTE'. This process is working.

But how is the way back working? How can we upload the content of this customized IDOC which we receive from a diffrent system to our ECC tables? Is there also a FM? Or ist this more comlicated? For standard IDOCs there are functions we have to enter in WE20. But what about customized IDOC structures?

Best Regards,

Lukas