How to delete a data pre-fixed in a dynpro, from batch input

Hi all, I'm trying to write a batch input function to make a return order.

I'm using BDCDATA, to fill fields in VA01 transaction.

When I try to fill it, some data in a field stops the batch input, and a message is displayed, because that data is not allowed...

The field that contents the value '010' (wich I want to delete) is: J_3ASZFH-J_3AKVGR7

I write PERFORM bdc_field USING 'J_3ASZFH-J_3AKVGR7' ''. but it didn't work...

Any idea?

If I go to the transaction, and fill all data, when I want to go to next screen it stops in this field and doesn't allow to follow up until the value '010' is deleted...

thanks a lot for your time!

MaEmilia