How to get UV maps into the model

[Wolf3D]

Hello Wings 3D users, I need some help: I am using Wings 3D as a beginner in 3D modeling and not as the main application. Wings 3D helps me to clean a model. It happens that I create a model in 3 different apps. I start in Sketchup which is comfortable for me, save obj file and import it in Wings where I make the cleanup and save DAE for some game. Lately I started to learn UV maps and made some in another app which works great for me. The problem is, that I have a file with UV map (png file) and obj produced by Sketchup. I want to merge them again in 3D Wings and produce a final result. I know how to import OBJ file and how to make DAE. But I do not know how to asign that png file with the UV map. I hope somebody maight have an answer for me.