[LSO] - Instructor Portal - disable settlement type

Hi,

We have implemented the LSO instructor portal at our client.

When I go to instruction and tutoring --> manage participation and try to book a participant on a session, I need to fill in the settlement type. I can choose between activity allocation, billing documents and free of charge.

Since we don't calculate any costs for the moment, I don't want this option. However it is obligated.

How can I remove this ? Is it customzing or webdynpro changes ?

Thx for the help