Setting network workgroup to "WORKGROUP"

I want my brand-new "MININT-PEBT00" USB-stick-PC to be in workgroup "WORKGROUP" (without reboot . . .).
Where is this to be typed in in WinBuilder?

forum-search for 'Win8PE domain workgroup' is unsuccessful.

You can use PENetwork > Start editor to set your network configuration/profile.

For some reason PENetwork won't start from within "MININT-PEBT00", when booted.
So anyway there is something wrong with my setup . . .
Any hints are highly appreciated !
How to fix this via WinBuilder ? 
Edit a script somewhere or download a little from someone . . .  ?

Can fixes be sent by email via oven-forum?

It is probably easier to repair PENetwork. It uses NetJoinDomain function

Got it now! Thank You !!!
The only inconvinience: I have to switch on 'network recognition' for my WLAN from within Win8PE manually to map network-drives of workgroup "MSHEIMNETZ" . . .

Is there a check-box for this in PENetwork/WinBuilder somewhere ?

With my new Win8PE-USB-Stick it's possible now to use this security-software for restorage reasonably:      

http:// w w w.duplicati.com/howtos/how-to-install-and-run-duplicati-2-0-preview

. . . don't forget to activate . NET framework 4.5 . . .