Select the shoe group. Hit ctrl D (duplicate).. Then hit Ctrl G to group the new shoe. Then in the channel box type -1 in the Scale X channel.
www.stevenegan-cgi.com
"Your weapons are no match for ours! People of Mars, surrender!"
"Um, this isn't Mars. This is Earth."
"Earth? Earth-with-nuclear-weapons Earth?"
"Yes."
[long pause] "Friend!!"