For CO2 or HPA I would contact the local paintball teams, as they have the filling equipment. The other option is to use local gas-suplliers like Woikoski and AGA, get a 10 kf bottle from there, a filling station from a paintballshop or used from the boards and fill yourself. The second option for HPA is the diving clubs, buy an scuba tank and again a filling station from a paintballshop or used from the boards and fill yourself.
For Scenarios, your best contact would be these boards, here are frequent advertises about organized scenarios. Local paintball teams are also an option, but mostly the registered teams are playing supair-field based sport paintball. The guys to contact are Anssi Mennala and Kimmo Kainulainen, emails can be found on this site.
Mil-sim scene is mostly Airsoft based here in Finland, these boards contain mostly sport-based stuff. Also Milsim as a scene is getting a bit frowned at, as we are trying to get a sportlike imago for paintball in Finland to get some goverment support.
