You cannot see the skins in the hangar until you have been connected to the online servers for a few minutes as there is one file the server has to install before any of the skins are available.
Also note, if your computer has Vista or Windows 7, and the game is installed in the "Program Files" folder, you will never be able to manually install anything in the game folders as those folders have been redirected to some virtual folders on your computer. This is just how UAC works in Vista/Windows 7, which is why we moved our default installation folder to another location.
If you removed the "sound.res" file from the game installation folder, you will have to re-install the game or the next patch/update will fail. NEVER remove the "sounds.res" file. Custom sounds will override the default sound automatically, if the custom sounds are installed correctly.