Just wondering what the best way would be to attach gumpaste to the sides of a ganache covered cake. Ie. I have a cake with poured and harded ganache and want to add butterflies to the sides. The butterflys have thing wings standing up and off tha ecake so the only surface area I have to work with is their 'body'

You can use the same ganache you used for covering the cake to stick them on. Put some in a piping bag and use like royal icing. You will have to hold the butterflies in place for a while so they don't slide about, it will depend on how thick your ganache is/how long it takes to set. Maybe you could get some of that cold spray in a can, but I have no idea where from or how much it costs!