@Spooky
You need to make a DSDT.aml file for you motherboard by using either Koalala's ACPI Patcher or fassl's DSDT Patcher (Search for the threads on insanely), then when you have one, add it to /Extra.
The second part to enable 10.5.8 sleep seems to be the AppleIntelCPUPowerManagement.kext. It needs to be in your /System/Library/Extensions and left running. This normally causes a Kernel Panic, so most people would either remove it or use a Disabler.kext to disable it. A properly configured DSDT file with allow you to have this in /S/L/E without the use of a Disabler.
Hope this helps..