You are right, that's wrong :)

Size, contrary to the information contained in some recent emails that I have been receiving, does not matter. A point on a UV map is defined by proportion not absolute position. Which then leads to the question, are you sure that you are applying the map to the OBJ that you saved out of UV Mapper. You did save it didn't you? Another thing to remember is that in Poser 3 & 4 the first time a figure is loaded it reads the OBJ file and immediatly writes a geometry RSR. Thereon after it reads the RSR. (I learnt this the hard way, took me ages to figure it out :) The solution is to delete the Geometry RSR and force Poser to re-read your new OBJ.