Be careful!
As long as they are not providing you with the aircraft you are on thin ice my friend. Are you planning to rent the A/C? if so you can kind of get around the problem by having the company rent the plane from a flight club and then volonter to fly the plane. I would avoid to charge for anything since that might get you in trouble later. If you can get a clear ok from someone at the CAA ( yeah, right) or you are sure of the interpretation than make sure you get paid!
The optimal thing would be if the local flyclub would be approved for "bruksflyg" than that's the way to go.
But don't qoute me!