I found using the command 'quickly' when he was actually doing a poop helps as he eventually associated the word with the action, and before long pooped on command but you just have to be patient. Are you using a different command for his wees? I use 'hurry up'. I crate mine at night (he's 18 weeks old now)he goes to be at 10.00pm and he doesnt wake until 8.00am when i get up, i then put him outside (has slept through the night from 10 weeks). If he should wake earlier which has happened twice, i get up go down let him out, when business done return him to crate without saying a word. He soon settles back down. Hope this helps.