Install of aftermarket alarm help

I have a 2004 jeep grande cherokee and i have installed a aftermarket viper alarm i have everything set up and working but i can not get the doors to lock and unlock i have read that i have to buy a programmer to undo the factory alarm, but unsure if this is true, :confused: i cant find a answer online at all. anybody have info or experience on installing a aftermarket alarm that could help me out thank you in advance