The other suggestion is to stall up the auto before you leave the line, left foot firmly on the brake, put it in gear and put your right foot down until the revs are up a bit, then when you get the green (well, ever so slightly before, taking into account reaction time) take your foot off the brake and flatten your right foot to the firewall. Only way to find out how high to let it rev while you're stalling it up is experiment, you want it just below where it starts to lose traction and do a burnout, so it might be as high as 3000rpm, or as low as 1500rpm. You do have a tacho, don't you?
Oh, and as XA Coupe mentioned, you might get a slightly better time if you shift the gears yourself instead of letting the auto choose when to select the next gear, but that also depends on where your engine is making the most power - if it's making power beyond 4000rpm, but your auto shifts earlier then that, then obviously you'll do better if you select the gears yourself and shift up to second and then 3rd just after it's reached peak power, whereever that is in your rev range.
Hope I've been able to help, wish my XF was worth taking to the 1/4, as it is now, I'd get hammered by a stock standard manual 2.0 Escort down the 1/4, hahahaha!