Timing Problems

Im Replacing The Timing Belt And Head Gasket On A 1998 Dodge Carravan For A Friend Of Mine.i Have Got Everything Off Except The Timing Belt And Head. I Cant Get These Items Off Because Of The Plastic Housing That Runs Inbetween The Belt And The Block Making It To Where I Cant Take The Cams Off Without Removing The Timing Gears! Does Anyone Have Any Suggestions On Doing This The Easy Way And How Its Possible Without Taking The Motor Out? I Really Need Some Advice Because I Just Started On The Van Today And Need To Be Done Tommorrow. Which Is Friday! Thanx Alot.