4.0 jailbreak iPhone 3G?

basically i have an iPhone 3G currently running 3.1.3 and jailbroken using Spirit……
i want to update to 4.0 but everywhere i go says “dont use this if you have used Spirit”
what do i need to do to update to 4.0 and jailbreak it?
i have already downloaded the following but not used any of it:
sn0wbreeze
redsn0w 9.5 beta
iPhone 3G 4.0 firmware

You need to wait until Spirit is updated or a new tool is developed.