My queen bee was like that. He was with the ladies and had no interest in breeding. My back up kingpin that I decided to use in case the queen wasn't up for the challenge had no problems locking with the females. I let him lock 2 of the girls just once and as soon as he was done I took him away. I put the queenbee in with the 2 females and it was like a switch was turned on. He has been a locking champ ever since. Now I just hope he has the lucky bullets and not the king.
So just give him a couple days in with each girl and then a break for some R&R.
And I totally agree with Roach. Wait for a nice storm. That tends to get them in the mood.