Enter tax amount in travel expense

Hi all,

I am new in TM module and I need your help.

I would like users to enter the tax amount in each travel expense manually. Is it possible?

I was looking for this in customizing but I don't find the corresponding field where the tax amount can be entered. I have found the field FWSTE of PTK03 structure, which it seems to be a good place to store tax amount, but I don't find how to enable it in customizing.

Can you please help? it is quite urgent...

Thank you very much in advance.

Best regards,

Nekane.