your asking for trouble
Do not do it that way!!! All Plasmas are ment to be ship up right and if the screen brakes when moving it, it is not covered under the warranty. Best to pay the extra $50 for them to deliver it and if they brake it they pay it.
You can also get some shipping straps to hold it in place in the truck and then some wood to displace the force from the straps so it not put undo stress on the tv it self.