creo4 config.pro option documentation for: PREFERRED_SAVE_AS_TYPE 
preferred_save_as_type
*.prt *.igs *.set *.vda *.neu *.stp *.ntr *.ct *.cat *.stl *.iv *.obj *.slp *.unv *.wrl *.enm *.evs *.mdb *.edn *.emp *.evs *.edp *.gbf *.asc *.facet *.sat *.model *.ed *x_t *.ed*.jpg *.shd *.eps *.tif*.pic *.zip
Sets the order of the file types to customize the Type
list in the Save a Copy
dialog box.