Hi
Our nearly 6 month old does the same, well he did around 5 months. He goes into his crate at 10pm, we dim the lights and then he went through till about 4.30am, myself or partner would come down, let him out for a wee on a lead so he knew it wasnt play time, then straight back to bed, unfortunately we had to wait sitting on the sofa till he finally gave that sigh of "ok im settling now". we would then go back to bed, but on a working day, this was pointless as we get up at 5.45 anyway.
I would suggest you do what you would with a toddler, take him out, no communication, no fun signs, just do what he needs to do then give reassuring effort back into his crate and hang about for 5 mins quietly out of sight. This may take some time for him to realize its ok but it worked for us and we didn't know where to start
Good Luck....
oh and we are at the beginning of the teen stage... i might need the luck also!