I don't know the diablo trick you are talking about but I can help you with the corner settings:
Set the corner instructions so that your fastest defender with good heading stays back, set eight players to stand on the far post and then set a player with good long shots, composure and finishing to stand outside the area. On a normal 4-4-2 formation it should look like this.
DR Stay back (remember doesnt have to be your RB)
DL Stand on far post
DC Stand on far post
DC Stand on far post
MR Stand on far post
ML Stand on far post
MC Stand on far post
MC Stand on far post
FC Stand on far post
FC Outside area (Doesnt have to be a FC)
If there is some other corner instructions you are refering to then i'm unaware.
In your Corner tactic, Did you set the corner to be kicked to the outside area then CRAVEN? To the Kicker? Or Penalty area or front post or what? I assume it's to the outside area, but just confirm this for me, please.