EDI ORDCHG: 00347 error Update item quantity of Sales Order

Hi,

I'm trying to update the item quantity of a Sales Order and I can "execute" the idoc in foreground mode, but in background the idoc finish in status 51 with the following error: error no. 00 347: "Field VBAP-MATNR (1) is not an input field".

Ho can I solve that?

Input parameters in Idoc are:

- Segment: E1EDP01

      Item 000010

      Action: 002

      Quantity X

    - Segment: E1EDP19

         Identif: 002  (I tried 001 too, but it doesn't works)

         Material: YYYY (material Customer Code)

And in table: NASTMSGENQ (customizing SPRO)

   I add the register:

       - Transaction Code: VA0o2

       - A. Func: 00

       - Error: 347

            ----> Information

     As I understood with this configuration if this error appears it will be an information comment and not an error. But it doesn't works in this case too.

Thanks for trying to help.

Regards