Looking for advice rom emale soldiers about clothing?

this is more for the canadian military but it also could apply for the u.s. military. i am very much a tom boy and built very boyish, kind a like ellen page (30a/23/30 measurements). i am a canadian army cadet and when not in uniform i wear boy's briefs (the ones boys wear) but when in uniform i am in girls panties and bras witch bugs me allot. what i was wondering is when i am dressed in my combat uniform, would it be ok to wear boys briefs and no bra or am i stuck wearing girls underwear? do any female soldiers wear men's underwear under their cadpats (acu in the u.s. or the bdus for the old timers). thanks or any replays