Hi,
I've just bought a new fork with post mount but my brakes are the formula oro (IS mount). I already try to use a normal adaptor but the caliper doesn't fit the rotor, the caliper almost hit the spokes. Is there any specific adaptor for the oro brakes? I use a 160 mm rotor.
Thanks!

Are you sure they are IS mount? Pretty much all disc brake calipers are post mount and use an adapter to mount them on a IS frame or fork. The caliper should bolt right onto your fork and work with no adapter for a 160mm rotor. A picture of the caliper would help.

A photo might be of help, a google image search of this model brake shows it as a post mount brake.