Personally, I figured once you found out how the attack spread works that would answer your question
Spirited charge effects the charge attack, which gets the +2, does not get the extra damage from the power, and is not part of the full attack.
After that you get a full attack because of the power, it does not get the +2, it does get the extra damage from the power.
Although, thinking it over, I dont know if it works that way.. are you charging or are you just going along for the ride? So, could you even benefit from the power? After all, you are getting the benefit when you charge, not necissarily when your 'mount' charges..
Anyone know the answer to that? hmm..