05 BMW 325 CI Keyless upgrade

Hi I recently tried to install DEI AM-1 keyless entry upgrade into the BMW 325 ci, I was told by DEI tech support   that you cannot install a keyless entry upgrade to the factory key remote. I program the system to learn the door lock polarity, but it will only work once in while, when the vehicle is started, it some how loses the program, will not chirp and the led will not flash. I was told that the door locks motor wire are progressive and alternates polarity, is this true? Has any able to install keyless upgrade to this BMW, and if so is there some trick or do i need to the one of doors for motor wires?    Would greatly appreciate any feedback or suggestions Thank you for your time

good luck with any info i have asked people about the new bmw systems no one can give me any info

if its a new one e46 body style the dealer plugs the computer into the car and sets the drives priority w/ that , so when the computer sees a negative pulse on unlock wire, it unlock all doors or just the drives door depending on what its programmed to do