I am also looking to compose music for anime(which being not japanese and not in Japan is impossible, one it's because of all the damn paper work, two Japan has this crazy work visa thing. Anywayz you do not see the anime you are writing music for, you are told the seen or what they want for the music, you do not sync the music to the anime.)there is not enough time to do that) So say you create some song as a piano arrangement, then that song you arrange as the production(maybe a jpop group plays it as the op, that song is also the theme for one of the characters, so you arrange that to strings whatever, also you create a lot of background grooves and other themes to fit what they tell you, intense music, feeling of sadness etc...Fl Studio would get you going on your whole production for groove style music, but not composition, which is ok^_*(after all you just need a piano or keyboard(some instrument), pen and staff paper. If you know someone in the industry the impossible becomes possible, even just doing some hard techno tracks to add to a the bgm, it could be done.
A lot of directors for anime movies will look for some outside talant to add a few tracks to an anime movie)look at the people who did the music for Masumune Shirow Apple Seed Movie)(but generally the whole anime bgm is done by the one composer or two or three in japan. If I had a big studio and could have any musician at my finger tips I wouldn't even use a computer. Also Film scoring does not mean just composition, what you are doing now could pass for a lot of films! Good Luck Man!