It seems my post for yesterday wasn't posted correctly for some reason... .
Thanks everyone, you are all so nice! It's great knowing I can count on you for advise; I feel way more confident

. I wanted to let you know we had two very successful nights: in both cases, Lucien ate, slept, woke up at about 12pm, played a bit and then slept the whole night! He did not cry at all until 6:30am (he only cried a bit during the day, but mostly to get attention). I have mostly figured out that if he starts nervously wondering in the x-pen, whimpering, it's potty time. I'm glad he is reluctant to "go" in the x-pen, even though the surface is a bit big.
My only concern at the moment is that he bites EVERYTHING, from my nose (lol) to his bed. For now, when I find him chewing on something he is not supposed to I say "NO", take that away from him and give him one of his toys, saying "this is ok!". Not much progress so far but we will get there!
He has also been eating more, but I'll ask the vet if I can mix some wet food, as some of you suggested. Tomorrow we are going to the Sheltie club in the FCA to get his papers, so he is meeting his breeder again. It seems they miss him... .
@marygirl: I'm not sure they have puppy classes here... . In fact, we don't even have handling classes. The FCA itself told me something along the lines of "go to a show and and ask a handler to teach you" :/.
By the way, here is a pic of him being extremely busy:
http://a3.sphotos.ak.fbcdn.net/hpho...0095082454347_566169346_5906260_8156510_n.jpg
Ah, puppy life! xD