Anyone have a Dodge/Chrysler w/factory DVD player?

I have a Caravan SXT with rear overhead factory DVD player but it does not have wireless heaphones like the Grand Caravan models do. I'm wondering if anyone out there has any idea if these can be added on? I don't know if the IR transmitter is something that can be purchased and added on. I know I can buy headphones but they aren't going to work unless there is a transmitter installed. If anyone has a Dodge with factory DVD player and wireless headphones, let me know where the transmitter for the headphones is located. This will help me narrow my search. Does it come from the LCD screen, radio in the dash, DVD changer, etc?

I can't get a straight answer from the dealer. I just want to add the capability of wireless headphones found in the grand caravan to my caravan.