I wrote a little bat file to load the wireless drivers from the host computer. It works on the couple of computers available to me but I can't test it further. The contents of drivers.bat are:
rem @echo off
setlocal ENABLEEXTENSIONS
path=x:\windows\system32
set wd=%cd%
set KEY_NAME=HKLM\sys\ControlSet001\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318}
rd /s /q %wd%\wireless
md %wd%\wireless
set /p z=[Which drive is the windows folder on that you wish to examine? eg c, d, e]
copy %z%:\windows\system32\config\system %wd%\sys.hiv
reg load HKLM\sys %wd%\sys.hiv
FOR /f "tokens=1" %%A IN ('REG QUERY %KEY_NAME% /s /f " wireless " /t REG_SZ') DO (FOR /f "tokens=3" %%B IN ('REG QUERY %%A /s /f "infpath" /t REG_SZ') DO (copy /y %z%:\windows\inf\%%B %wd%\wireless))
FOR /F "tokens=1" %%G IN ('find ".sys " %wd%\wireless\*.inf') DO (copy /y %z%:\windows\system32\drivers\%%G %wd%\wireless)
copy %wd%\wireless\*32.inf %wd%\wireless\1.inf
reg unload HKLM\sys
attrib -h -s -r sys.*
attrib -h -s -r sys.*.*
del /q sys.hi*
del /q sys.*.*
X:\Windows\System32\cmd.exe /c pnputil.exe -i -a "%wd%\wireless\1.inf"
%z%:\windows\system32\taskkill /f /im PENetwork.exe
"%programfiles%\penetwork\PENetwork.exe"
I put the file in the root of my usb stick, boot from the stick WinPE 8.1 then run the file. The wifi drivers get loaded and I then open the PENetwork tool, connect to my wifi and enter my router wifi password and everything works.
I came across an interesting bug. My own network drivers are net8192se32.inf and rtl8192se.sys. The inf file would not process unless I renamed the 32 to something else eg. 31 so I had to add a line in my script to copy and rename it. Maybe the same happens with a 64 or x86 in the file name - I don't know.