[phenixbb] Ion placement (anomalous) + occupancy refinement

Hi everyone, I have a dataset from a protein that contains 2 Ca2+ binding sites. The Ca2+ loaded protein was crystallized in the presence of Tb3+ which at one site mostly replaced Ca2+, however at the other site the Tb3+/Ca2+ ratio appears to be much lower (judging from anomalous map; data collected at 1.3 Å wavelength, MR for phasing). The occupancy sum of Tb3+ and Ca2+ at each of the two sites is strongly believed to be 1. While I am aware of the ion placement option in phenix.refine, I am not so sure how to refine the partial occupancies using anomalous data, if possible. Many thanks for any hints, Miha