W/M and Bow (and /S?)

Hey,

I've noticed a M/W with a bow in a bow slot. Can I put a stated bow in that slot if I'm a W/M or do I have to be W/M/S? Also if I'm W/M/S and have a bow in that slot and are switched to W/M are the stats actually active? Do they count towards my total stats on that character or only when I'm using S side?

Thanks! That's what I was afraid. So no point stating a bow then.