The slipstream process of Office 2007 is a simple two step process:
- Extract the SP1 file
- Copy the MSP files to your install share
Download Office 2007 SP1 here: http://www.microsoft.com/downloads/. Save the file on the root of your D:\ drive. Create a folder called D:\Office2007MSP\.
Extract the SP1 file with the following command:
Open the folder D:\OfficeSP1MSP
Copy all the *.msp files to the Updates folder on your install share.
If you run Setup.exe the setup wizard will install Office 2007 SP1.