The only way I see doing it, and if there is a better way someone post it. What you do is, go through every different kind of static mesh in you map. Not the stock ones, everyone has these and your .USX file will be bigger. What you do is right click a SM and select convert to Static mesh. A window will pop up. It is important to remember what you put for the package name because you have to put the exact same name for all the meshes you put into the package. Name the group and mesh whatever you want. After you have done this with all your SM's. Close the editor. It will prompt you to save you package. select Yes or OK whatever one, and name the package the same as before. you may have to add the .usx at the end. Reopen the editor, go to your SM browser, and open your package. It should be with all the other packages, so no neet to search around for it.
Now the only thing to do is delete all the SM's in your map and replace them with the ones in your package. Backup your map file before you do this because I have never done this, and I can't say I'm sure it will work.
Happy mapping.
