hello pedro, sorry to respond so late, I've been away on holday and unable to test this myself

Now I followed the same guide you followed and also I have been unable to connect to the server. After windows tried to verify the username and password it wouldn't pass the connecting part...

It simply shows an 800 error.
Also, doesn't L2TP use port 1723?

things you could try are to place all the configuration scripts on the flasfs instead of harddrive, just in case.
Also you can just entire folders to the .files like:
it will save that folder including every sub file/folder