pg 155 of the PHB
Since the bull rush note is a subset of the paragraph entitled "Attacking on a Charge" it would appear that the bull rush is indeed a substitute for the normal attack, as is overrun.
Now using the rules logic of Hyp - that is you move on the charge until you threaten, make your attack (from the charge) and then continue into the foe's square. . .
Hmm something is wrong here since you stop your movement at the point of making the attack and it would require an extra move to move into your foe's square (which is required for a bull rush). But then again I could be misinterpreting his post and reading that he is saying you can move,attack, continue move and bull rush (but somehow I don't think that is likely, I just think his post wasn't as clear as he normally is).
Based on rules of movement and attacks, you can't take an attack as part of a charge and still perform a bull rush (without some special feat or class ability that may exist).
Attacking on a Charge: After moving, you may make a single
melee attack. Since you can use the momentum of the charge in
your favor, you get a +2 bonus on the attack roll. Since a charge is a
bit reckless, you also take a –2 penalty to your AC until the start of
your next turn.
A charging character gets a +2 bonus on the Strength check made
to bull rush or overrun an opponent (see Bull Rush, above, and
Overrun, below).
Even if you have extra attacks, such as from having a high enough
base attack bonus or from using multiple weapons, you only get to
make one attack during a charge.
Since the bull rush note is a subset of the paragraph entitled "Attacking on a Charge" it would appear that the bull rush is indeed a substitute for the normal attack, as is overrun.
Now using the rules logic of Hyp - that is you move on the charge until you threaten, make your attack (from the charge) and then continue into the foe's square. . .
Hmm something is wrong here since you stop your movement at the point of making the attack and it would require an extra move to move into your foe's square (which is required for a bull rush). But then again I could be misinterpreting his post and reading that he is saying you can move,attack, continue move and bull rush (but somehow I don't think that is likely, I just think his post wasn't as clear as he normally is).
Based on rules of movement and attacks, you can't take an attack as part of a charge and still perform a bull rush (without some special feat or class ability that may exist).