Retain V4/M4 clothing morphs when fitting them on DAZ 3D's new Genesis figure by converting the clothing item to a weight-mapped figure and then using the Transfer Utility in DAZ Studio 4 Pro to fit the clothing item on Genesis.
I understand from several posts on DAZ 3D's forum that the latest DAZ Studio, version 4.5, has an auto-fit tool that retains the morphs. At this point in time I wouldn't use version 4.5, as it is at Release Candidate 2 stage and users are still reporting a lot of issues.
Update (Sep. 10, 2012):
DAZ Studio 4.5 has been out for quite some time now. I suggest you get it as soon as possible while the Pro version is still free.