Shield Slam says you bull rush the target of your shield bash attack using your attack bonus rather than your combat maneuver bonus. Do you apply your +2 or +4 bonus from Improved Bull Rush to that attack roll?
For example, my fighter attacks a troll with his shield, getting a 35 on his attack roll. He rolls damage as normal, and then bull rushes the troll as if he had rolled a 39 on his combat maneuver check (base 35 from the attack roll + 4 from greater bull rush). Because the troll has been successfully pushed back, my fighter gets a free attack of opportunity against him. Is that right?
Okay, spot on except that it states in the Greater Bull Rush feat description that all allies, but not you, get an attack of opportunity against him. So no, you can't just keep pushing him for a mile in one round.
Thanks!