Hi,
I have with my daughter, well she is now 6 years old! IT worked out great for me! I suggest that you try this, for my daughter had trouble latching on. I also used the Supplemental Nursing System from Medela! I would put breastmilk and fourmla, not at the same time, and make shure she was getting her right amount of food!! Good Luck and God Bless!! Oh I am also on a site called www.breastfeeding.com, that might help you too!