learn to screamo scream

i finally learned how to scream,
but i need help holding it, an its realy hard for me to change my ranges,dose it have something to do with me breathing?

watch this hes fucking crazy,I LOVE IT!
http://www.youtube.com/watch?v=pVDLs3WimdU
He screams for like 1 min non stop!!!,,,,wow

Me and my band{my final resting place}just booked our first gig-ever!
And i love the song we wrote, but we already have a main screamo vocalest Even, but we would sound way better if we could both scream,like we planed,,,if i could scream the hiigh parts because he has a deep voice but i cant do it all the way,i only get a wisper and i want a waay more powerful high pitch scream.i dont wanna let them down:( & i dont wanna blow this….