Scenario for interface between a non sap system and a SAP erp

Hello,

I need some help in order to elaborate a interface between a SAP ERP and a non-sap system with the help of a XI system.

- At first regarding the interface from the non sap system and a SAP ERP :

the non sap system sends a flat file to the XI system. The flat file contains a row with header data and rows with item data. We were thinking when the file arrives to the XI system, to save the data in a header database and in a items database in XI. is it possible ?

And then to have like a job that reads the database and creates idoc and sends them to the SAP erp and updates the xi header and items database with a flag that means that the records have been sent to the SAP erp.

- Regarding the interface SAP erp to non SAP system:

the SAP erp sends idoc to XI. Then the idocs are transformed into flat file.

Is this scenario possible ?

Do we need any adaptator between the non sap system and the XI ?

Thank you for your help

Christophe