I'm assuming you made this character from scratch, right?
Or is it safe to assume that you have the full permission from the original creator to Poser-ize this figure, right?
 
If you answered NO to either of these questions, then don't even think about trying to Poser-ize the figure without the original artist's express permission.
And when you distribute the Poser version, don't forget to give the original artist credit for making the mesh.
 
Although the artist will probably give permission (especially since this is a free item), you should always ask permission before converting to another file format.
 
--John

VanishingPoint... Advanced 3D Modeling Solutions