P90X & weightbench

Ok, maybe this is a really dumb question, but if you don't have the space for the pull-up bar and no space for bands to attach correctly to a door for the exercises required for back workouts - Is a lat pull down bar extension on a weight bench pretty much gonna be or do the same thing though for me? I have one of these cable pull-downs on my weight bench that you can add free-weights to, but have never heard anyone ever mentioning them being used for p90x.
Also, if it can be used in the same manner as the bands or pull-up bar, do you follow along with Tony and the others technique on the pull-up bars, or should you follow the bands technique? Like for example, do you lean back further (like with the bands) or sit almost straight in front of the bar like you are doing an actual pull-up with a stationary bar?
Again, sorry if this all sounds confusing or dumb, i just have little experience in the strength training side of fitness. :happy: