So as you may have noticed if you try to install the B2C client with an internet connection on the version you'll get won't let you anymore use the offline flash method, but here is a little fix!
What you have to do is to install the B2C client from the normal installer and than proceed with these operations:
-First delete the content of this folder "C:\ProgramData\LGMOBILEAX"
-Than extract the files contained in the zip attached to the previous folder (LGMOBILEAX)
-Make two directories "B2C_Client" and "Language"
-Move everything but "LGMLauncher.exe" to "B2C_Client" folder
Now you have a fully working B2C client, remember never to lunch it with internet connection on, or else you'll have to do this procedure again!