HikaShop Content Module and SEF URLs gives 404

Hi When I turn on Standard j1.6 SEF urls (Search Engine Friendly URL = yes, Use Apache mod_rewrite = yes, Adds Suffix to URL = yes)
I get a 404 when I try to access the catalogue from the HikaShop Content Module.
Is there a correct setting for this or does SEF urls simply not work with the HikaShop Content Module?
Appreciate any assistance.