You may want to take a look on this site to get another perspective: Multi7PE
Also here people are doing all kinds of booting type stuff: reboot.pro
As for the line in the step, it looks like it's copying imagex program to the image in case you want to run it from the Disc. Just replace <version> with the name of the WAIK folder if using WAIK and <architecture> with x86 or amd64 or whatever your processore platform is. I played around a bit with WAIK but it was a few years ago. Never got into it heavy.
It's probably a bit easier to use a wrapper tool that itself uses WAIK. Saves you from some of the nitty gritty details.