Update hidden fields using SM31 transaction

Hi,

I would like to update some fields table automatically when I used transaction SM31. For instance:

My table fields:

- BUKRS

- VTWEG

- SPART

- TEXT

When the user go to SM31 and create a new entry: DM01, 10, 10 , I would like to fill automatically field TEXT with word 'Example'.

How can i do that ??

Regards,

David