Delta not returning new files

Hello!

I am having a problem and I hope someone can shed some light on it.  A user renamed a top level directory thus making our internal app think that all of the files it had were "deleted".  This would not be a problem because it would see the new directory name and think these were all newly uploaded.  The problem is that the delta function is not giving us the information on these "new" files.  Instead it just returns the delta string.  I have tried using an old index string from about 4 months before the renaming incident happened and the API happily shows us all of the "deleted" files but none of the "new".  Passing a null delta string only gets us a new delta string and no file listings at all.

Any ideas?