SLI and Mac OS X

I’ve recently figured out that my MacBook Pro (alu late 2008 with GeForce 9400M and 9600M GT) support SLI by hardware but cannot be used due to software (OS X 10.6.x; mine) limitations;
Now, suppose that I want to write a kext in order to enable the SLI functionality and use both 9400M and 9600M GT together (under AC power)… how may I achieve that ? Where should I start ?

Thanks in advance! :)