Assuming the dynamic clothing lines up with a zeroed Genesis base, just go to Edit>Figure>Transfer Utility. Pick Genesis as the Source, the clothing model as the Target, and click Accept. Most likely the clothing will be made for an older figure - if so, under Source Shape select Clone shape and then select the figure from the list, then expand the Transfer Utility dialogue by clicking the Show Options>>> button and check Reverse Source Shape from Target. That should give you a version of the clothing that works as a conforming piece - it won't, however, work if the clothing is modelled in a way that is far from its rest state (such as a cape laying stretched out flat at neck height, from which it would drape to the figure when the simulation was run).