Personally I'd rather have them within mappero. It is after all, quite a mature piece of software and has plenty of other maps in it; most notably open street map. So, dear Orava, would you be willing to share the secrets of how you tease the maps out of paikkatietoikkuna
And perhaps tell a bit about the license: E.g. http://www.maanmittauslaitos.fi/node/3960 Says that I have to pay at least 244 euros to get the maps via WMS.