Inbound REMADV IDOC

Hi All,

We are receiving a remittance advice in the form of IDOCS(REMADV). Can anyone guide me on how to process the IDOC in my system. Customer sends the IDOC with partner number as vendor number which is stored in their system. I wanted to know how the mapping happens between the customer number maintained in my system to vendor number that customer sends.

Which filed should I use in my system to maintain the vendor number created in the customer system.