So your trying to Flip the Object over the Axis (in a mirror like manner) but don't actually want to Mirror the Mesh or duplicate it???
In your Channels Box, with your object selected. Type "-1" in the "Scale X" Channel.
Now thats what i think you mean though i could be wrong.
If wrong Just post back with some more info.
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!!"