This is how I do that! Make a Level of Details and suppress all parts that you have inside (not visible). It will reduce file size. Use a srinkwrap command http://wikihelp.autodesk.com/Inventor/enu/2012/Help/0073-Autodesk73/0460-Assembli460/0536-Represen53... (using the Options "Solid body keep seams between planar face"). And do not forget to break the link with base assembly. After, just save the file. In case you can also make Edit derive - and choose option "Solid body keep seams between planar faces". Because some times after Shrinkwrap command it is still consists of several solid body. Then you will get a single protected part. It is also depends what soft is using a customer. You also can Exported file to step. or sat. Good luck!
