Multiboot Windows2Go and Win8 Setup from USB disk

#1
Hi all!

I want to build up an ultimate administration tool with my usb HDD which can boot up a completely portable windows and also initiate an windows setup for the local drive. First for Win8 and later eventually for Win7 and XP...

So here is what I have:
1. I installed Windows2Go on my USB drive and everything working correct. I have a full blown windows with disk image tools and so on. I installed EasyBCD to manage the bootloader. Everything is working.
2. I have an USB stick with a working Win8 setup, created with eg Windows 7 USB/DVD Download Tool - Download - CHIP Online

The easy plan which failed:
I took the .iso image of the Win8 setup disk and added it with Easy BCD to the boot menu.
It was possible to boot into the iso with the Win setup but when it comes to the point to select install partition it can't show any disks and asks for disk controller drivers. With the recovery console of the iso, it is possible to see all partitions (local and those which are on the USB HDD).
Anyway... I found out that the EasyBCD iso feature does not support windows setup disks. That was the point where I stopped trying to use EasyBCD iso feature.

The new plan is to transfer the partition of the USB windows setup stick to free space of the USB HDD and then change the bootmenu to also show a windows setup entry. The copy of the partition should be no problem but I don't know what I have to configure in EasyBCD to make a new entry for the copied partition.
I hope anyone can help with this?