Ark and Zip: file dates question

One thing alway perplexes me about KDE's Ark and InfoZip's UnZip. Name, when
viewing or extracting a zip file prepared with PKZIP under DOS, all files
in that archive will appear with the same file date, and all will be
extracted with that date. But if I open up a xdosemu window and then use
PKUNZIP, the correct file dates will appear in the archive and be extracted
as such. How do I get Ark and UnZip to honor the actual file dates within
the archive upon extraction?

I have Googled this and came up with nothing. Man pages for UnZip don't seem
to help with this either.