sounds like fungus.... and there's a couple of things you may want to try...
if the physan isn't working, then use a systemic fungicide. I'm not sure what brands are available in the states but get one that specifies that it is systemic.
the second is to look at the current growing environment. If it has happened since being brought inside, look at what may have caused this, eg. is there enough air movement? I find water sitting on leaves when there is no air movement causes this type of spotting (darn those horrible zygopetalums and their leaves! anyways enough about me and back to your problem)
well that's all I can think of, maybe others have had similar experience and know of other treatment.
oh, unfortunately, as long as those leaves are on your plants, so will the black spots... it just won't go away, but you can try and stop it from 'spreading'.