If you have a dos section prior to the OS install, you can do it there. I have never seen anything that allows you to do it via the unattend.txt. I use AEFDisk in a dos session just prior to the OS install. I create a C partion of 2 gigs. Then, create another partition of 33gigs. I will use the ExtendOEMPartition flag in the OS install to get the full 35 gig C drive. After creating my 2g, and 33g partitions. I create another, last one I promise, that is 10g. Then I delete the 33g partition. This leaves me with a 2gig'er to perform an install on, a big blank space in the middle of the disk to perform the ExtendOEMPartition on, and finally the remaining space is the 10g D drive. AEFDisk is a great tool. I've been using it for 5+ years and it has never let me down.