you have to import first sa model with sa plugin kam's script and then delete all green tabs linked with the model (IN SCHEMATICAL VIEW)and remake the hierarchy with GIMS/tools/HIERARCHY MANAGER. set:model(not collision) and set node or dictionary(node for single models and dictionary for odd models>wdd)
you need also to convert sa materials(shaders properties) to gta iv ones so click on the Convert Material tab in tools.
if you have any fail in the material in scene display, it means that the textures dissapeared and you need to reimport textures.
before Converting material you should go to material editor in tools(GIMS) and convert materials one by one, clicking on the materials.
after that, change shaders if needed and reimport textures if they dissapeared and then you are able to export(odr-odd format)
export it and then import odr-odd file to your game archive(img-rpf) by using OPEN IV program.
if you have any question just PM me.