I wanted to call your attention to a great new member submitted article-- Creating a driver installation in an MSI can be a challenging task. One of the more popular methods to achieve this is to use Microsoft's Driver Installation Framework (DIFx). Microsoft provides documentation on DIFx, however it is limited and doesn't provide any examples. The article at the link belowprovides a step by step working example of how to achieve this task. In the step-by-step, Jeremy Boyes walks you through creating a Windows XP installation for a Signed Driver: Synaptics Touchpad with Wise Package Studio.

http://www.itninja.com/blog/view/driver-installation-from-an-msi-using-microsoft-difx