1) Get a bank account
2) Get an accountant
3) File notification of a business startup (no permit required for EEA residents, though photocopy of passport is required if you do not have a finnish id number) (takes 1 week)
4) Wait 2 months (You need company accounts to show the police to prove you're making a living as a capitalist pig).
5) Goto poliisi with accounts showing you're earning/paying taxes, complying with the laws regarding conducting a business in finland.
6) Wait for verdict, and pray they don't kick you out of the country.
7) It'd be nice to have a plan B.
I do wonder if I have to charge VAT on services rendered to yankland, it's not a killer, but it would help my budgetting to know this before a substantial proportion of my earnings ends up in the taxman's pocket.
I'll inquire about this tomorrow, but if anyone happens to know about VAT / consultancy to a non EU country I'd would be extremely grateful.
I realise I'm quite screwed given I probably don't fit into one of the neat little boxes the police have for EU immigrants, and EU law seems mainly concerned with employees or large businesses not entrepreneurs when it comes to your right to reside / do business in other EU states.
I was aware that finnish taxes operate a prepayment system (not a lot of fun, but can't be helped).
Help and comments always appreciated, no matter how sarcastic or bleak

If anyone can suggest any sensible plan Bs which don't result in the police telling me to piss off (as Hank would put it), there are far too many ifs/maybes in this, and having an application turned down after 5 months resident in finland would be far worse than being told to go away before even entering the country.