This function returns the GLN of a location of the trading partner in question as an argument and returns the stored BackendReference-ID of this trading partner location. The BackendReference-ID links the eBiss-TradingPartner-Location to the partner location stored in the ERP system. All locations looked up by this mapping function are stored in the location cache of the mapping context and are available to other lookup functions. \
The second argument can be an Auto-Add-Value (True, False). If True is specified, the GLN is created if it does not exist. The functionality of the second argument (Auto-Add-Value) is currently not available.
TradingPartnerBackendReference('GLN')
TradingPartnerBackendReference('GLN', 'AutoAdd')
TradingPartnerBackendReference('4035811991014')
returns e. g.: 7001419