Try copying the Office installation files onto your desktop - browse to it with vlite and see if it will pick them .
If it does, you could probably slipstream Sp1, then pick the files up again and slipstream SP2.
Otherwise it can be done manually:
Copy the office files into folder named, e.g. Office 2007
Copy Office SP1 files into a folder named, e.g. Office SP1
Extract the Office Sp1 files into a folder named , e.g. Office SP1EXTRACTED.
Copy the .msp files from Office SP1EXTRACTED into the Updates folder in the Office 2007 files, burn to cd.
It should install the updates from that folder as you are installing Office .