I'm the same as Mads (except I didnt' do any controlled comforting - just went with his sleeping patterns as they were) but DS rarely slept more than 40mins during the day.. and has only in the last couple of months actually started having really good day sleeps. His night sleeping has improved greatly the last few months too. So I do believe babies 'get it' somewhere down the track, so I wouldnt' stress too much about 'training' him.

You also get to know whether they're ready to wake up too. I find now, if DS wakes after about 45 mins, but doesn't get himself up and is still lying down when I go in there, I know he's not ready to get up yet, so I quickly lie down with him, and he goes straight back to sleep hehe. If he's properly awake he just gets himself up and comes and finds me.

All the best! Actually 45 mins were LONG sleeps for us.. it used to be about 20 mins for a while there! You'll find it can change all the time. Try to go with the flow if you can