Originally Posted by Voidrider
...a handy trick to soften the rubber up a bit is to remove them completely from the bike, and BOIL then in water for a few minutes. Sounds goofy, but does really work. Don't lose or forget the boot springs.
Edited for clarity.
Can't emphasize this enough. Boil them for like 10-15 minutes and they should be fairly malleable. However - lose the boot springs. They're more of a PITA than they're worth. Swap them out for some hose clamps. It will make your life a little easier.