I haven't check it myself yet, but I don't think the DUF format is visible to DS if it's in a Poser runtime, so saving a material preset to work with a PZ2 is a non starter, especially as DS3 can't see them either.

What you need to do is save using "File > Save as > Deprecated > Materials Preset", this will allow you to save as a DSA, which is compatible with both DS3 and DS4.