Attached Link: http://www.uvmapper.com

In Poser 5 and 6 you can opt to turn off smoothing but since you have Poser 4 you will have to do something different. Pick up the free Lite version of UVMapper from the link. Then in UVMapper:-

1. FileLoad Model
2. EditToolsSplit Vertices
3. FileSave Model (use the default save options)

Now when you FileImport the model into Poser it will have crisp edges.