Since it is now two years since you wrote this post you have either solved your problem or found someone to fix it for you. For what it is worth, my wife bought me a chrome shift handle from American Muscle about two years ago for my automatic shifter in my 2002 Mustang.
I took it to Hometown Auto Repair in Finksburg, MD to have it installed after an oil change. Now Darrin who owns the shop is a top notch mechanic and it took him more than an hour to install this shift handle!
He was so determined to figure this thing out that he just forgot about time until he finally got it working. It is not as easy to install as American Muscle would have you believe. Now that it is in it does dress up the shifter but it was a lot of agravation getting it in!
Midnight Blue
MCOM Treasurer-Historian