You can certainly user C4D to create clothes for Poser characters. The R9 release with the add-on Mocca module makes it a lot easier. But... creating clothes for Poser is definitely not the easiest thing to do. From my own experience I would suggest modelling some simple props first, seeing how they work in Poser and what you need to do to get them from Cinema to Poser at all, before trying to make clothes.

Steve