Use grub to boot a windows on a usb device

I'm going to install a windows for test. But somehow I don't have a dvd device to do that.
So it consists of two steps:

1. Get everything ready on usb device:
a) Make a ntfs partition on the usb disk
b) Copy all of the data from installation dvd to the ntfs partition
c) Run the following command with a windows:

bootsect /mbr /nt60 e:

Suppose E is the partition number of the usb disk. You can find the bootsect.exe from the installation dvd.

2. Boot from the usb disk.
I have grub installed on the hard disk already. Once the grub menu is presented, press C into command mode, and input:

rootnoverify (hd2,0)
makeactive
chainloader +1
boot

hd2 is assumed that you have two built-in harddisks, so usb disk is the 3rd one(hd0, hd1, hd2).
And 0 is the first partition on the usb disk.

That's it. The system should boot from the usb disk soon.