Scientist must be lvl 9 and you can then train a science BO to have science team III it costs 225 star fleet merits.
Its that simple.
Go to the Status screen of the science officer you wish to train and at the bottom of the screen next to "promote" will be "train" click this to bring up a menu where by you can select "science team III" (the interface for this looks similar to the BO power vendor at stations) Then simply tick the box next to the science officer that you wish to train and its done.
I have it trained right now and have been putting it to good use for some time.
Good luck fellow boffins
P.S. BO star fleet rank is irrelevant to the training of a new skill, you just can't rank it up until you are the correct level.