Diane, I certainly sympathize with your dilemma.  This is what I would do.
 GO and do your talk the same way that you would always do.  There is a place
for ABM as a medicine.  Even a few our breast babies have only become
successful because of the use of ABM as a medicine.  M-J's ABM's are a
medicine when a baby has galactosemia, MDU disease and other metabolic
disorders that make it impossible to digest/thrive  on breast milk.  Do not
alter your talk.  If you talk about the risks of ABM to cancers, gi disease,
diabetes, then go for it.  If your talk is about breastfeeding, benefits, how
to, etc.  why change anything.  If you do not go, who wins?  Not you.  Who
loses?  All of the nurse managers who would benefit form your wonderful
information.  How many more conferences will formula companies sponsor if the
speakers talk the talk that you talk!!!!  IF you don't want to take their
money for honorarium, that is certainly up to you.  But please still go and
impart your knowledge and wisdom to others.

Linda in sunny southern california   Is it spring yet in NY?