is it in the daytime or middle of the nite that she falls asleep while latched on? have you tried giving her the pacifier to help her to self-soothe? if she has started on semi-solids n you have been giving her a bottle of EBM now and then, you can also try giving her a little bit of water thru the bottle to satisfy her need to suckle.
having said the above, every baby is different. my 11 month old still wakes up once on some nites to dreamfeed. i personally feel that at his age now, once a nite is still manageable and acceptable, not tantamount to chronic comfort suckling, so i can go along with it. but i agree that we have to avoid a situation where we indulge in too much comfort suckling as it can potentially become a hard habit to kick, as i have witnessed in some friends.