You have to set the center of rotation in cam, it makes it easy if you model the 4th and 5th in and keep the model in it's own file with the center of rotation as a sketch that you can pick easily.
Then what you do is import the model of the 4th and 5th axis into a new model then when it's set in it's correct position you import the model what goes on the 4th and 5th then go into cam and do the setup first setting the first cut positions wcs and picking the model and setting the stock then you do the first toolpath, then if the next toolpath is on a different axis you set it's position in the toolpath useing the wcs sketch to set it's wcs.
Have a look at this vid it will help there are other ones on the fusion youtube and hsm youtube channel as well