from your descriptions, i have the feeling that your workflow is based on some bugs to get the result you're looking for...
could you please submit a sample .sla and pdf (with screenshot in acroread and foxit) to show what you are doing?
(please keep the .sla as simple as possible)
but, basically, the reference for displaying PDFs is indeed acroread, so, if it works correctly there, it is unlikely that the bug is on the scribus side.
ah, could you also please post the link to your bug report in the foxit tracker?