Cavalier's Charge bonus on Bull Rush attempts?

[Tamago]

What is the interaction between the Cavalier's Charge ability and the attack bonus on a Bull Rush? Consider the following passages (emphasis mine):

Cavalier's Charge (APG Page 33) wrote:

At 3rd level, a cavalier learns to make more accurate charge attacks while mounted. The cavalier receives a +4 bonus on melee attack rolls on a charge while mounted (instead of the normal +2). In addition, the cavalier does not suffer any penalty to his AC after making a charge attack while mounted.

Attacking on a Charge (Core Rulebook page 198) wrote:

After moving, you may make a single melee attack. You get a +2 bonus on the attack roll and take a –2 penalty to your AC until the start of your next turn.

A charging character gets a +2 bonus on combat maneuver attack rolls made to bull rush an opponent (see Bull Rush on page 199).

I'm not clear exactly what the interactions are between these rules. If I am a 3rd level cavalier and I bull rush someone on a charge while mounted, does my Combat Maneuver roll get a +2 bonus (per CRB page 199), a +4 bonus (per APG page 33), or a +6 bonus (both)?

Is there anything else that I need to take into account when performing a maneuver like this?

Thanks!

[Adam Moorhouse 759]

I'm pretty sure it's your mount doing the bull rush, and your mount does not get your +4 bonus, as far as I know.