International return has never been ProSeries forte.  It is not likely to change.  Lacerte and PTO should be your choice if your practice has enough clients filing international returns.  If you need to prepare just a few, PTO, which runs on the same Lacerte engine and charges you on a per return basis, would be a good option.

Even if you look outside of Intuit, there are only a few tax products that are really capable of handling international returns.  And being capable is very different from just having the forms available.