That's like saying 'Drive into that concrete barrier at 120mph! But don't fuck up my bumper!'. Growl from below your lungs, if you try screaming the way you've described you'll be lucky to get away with polyps and nothing else.
First, breathe in with the gut - not the shoulders up and down, the stomach and ribcage coming out. Second, you need to find the 'depth' that your voice works with best. First, speak normally. Then try to shape a prolonged cough into a word - it'll feel 'lower down'. Then try barking like a dog or roaring like a bear, a bit lower and lower as you get used to 'pushing' your voice lower and lower past what you'd normally consider your throat. Eventually you'll feel like your voice has 'turned over' and while it'll sound like the philly cheesesteak you had for lunch is doing an impression of a dying moose - read: shit - you'll get used to it and be able to 'shape' it into what you want. Note that you're not going to sound like whoever inspired you to growl, as the tone and depth will vary with everything from size to speech type to experience, and more other things than one could care to count. I want to growl like Mikael from Opeth, but my depth and tone are more like Haven-era Dark Tranquillity. I'd love to sound as demonic and twisted as Devin Townsend on the 'duel' in Soilwork's 'Black Star Deciever' but I can't sustain anything that high up. All anyone can do is find where their voice is in its 'natural' place and work up and down from there.
On a side note, on the Live Apocalypse DVD does it almost sound like Angela is using a harmonizer to anyone else, too? Not talking about the parts where Mike is doubling the lines, just some parts sound like they have added depth that's just... unnatural. Maybe she's just really that scary, I don't know. Now that I think about it I'll try growling some stuff and seeing how a harmonizer sounds on it, just to fuck around - hope growls work well through SM57s.
Jeff