I know when in melee combat unless your character is using a weapons foci or killing hands you can only roll your willpower to attack with a power equal to your charisma. However, the rules say if using a weapon you gain the reach bonus. Now the question using the Cannon Companion, could a character with the maneuver kick attack use it against the spirit and gain the reach advantage? Further still, could he use the focus will and kick attack maneuvers? If his martial arts style gives him extra dice for the kick attack would he gain those as a bonus to his willpower against the spirit as a confidence bonus of sorts?

Yes, he'd gain the Reach bonus. No, he wouldn't gain the dice bonus, as those come from physical training instead of personality. Focus Will, however, would work just dandy. But note that you can only use one maneuver at a time unless it specifically states otherwise.

Just don't ask my why Reach works, though. I have no clue behind that, though I could come up with some bullshit answer about "focusing your will along the length of the weapon" or some such. But that's pretty much what it would be; a bullshit rationale.

EDIT: Actually, upon reading Focus Will, it only applies against materialized spirits (for some strange reason; why you would be using mental attacks against a materialized spirit is beyond me), meaning it only works when they're on the Physical Plane. Sorry.

Where are those rules about attacking spirits with willpower?
How do they work?

Sorry for intrusion on topic.
But then, common tactic is "wishing spirit leave"?

Under Physical Form, P188, SR3

A character using a high-reach (2) weapon and charisma 6 could successfully damage most spirits using a force of will attack. In-fact any spirit with a force less than 12 would probably take at-least some damage.

Take this situation:
Charisma 6 character with Willpower 6 wielding a No_Dachi (reach 2)
attacks
Force 11 City spirit

Character attacks 6 dice versus TN 2 and gets 4 successes
Spirit counterattacks, 23 dice (12 reaction plus 11 pool) vs TN 6 and gets 4 successes
Attacker wins ties
Character stacan't stage with no successes
Spirit resists 6M damage with 11 dice (force), rolling 2 successes
Spirit stages damage to Light

Not really, the fact that you use Willpower doesn't mean the normal unarmed/armed combat rules don't otherwise apply to both sides.

Given that, most spirits would Counterattack as per Melee rules and knock down your successes and have a target number of only 4 (maybe less if they have Reach).

[edit - Where did you get that Spirits can't counterattack?]

There was a discussion of this a while ago where I think it was decided that the spirit couldn't counterattack.

I just checked and corrected my post above. The rule specifically says that a spirit cannot use Combat Pool against a Willpower attack but says nothing about Counterattacking the melee attack with its combat skill (in this case Reaction); However, while I can see why some may read it as such, the rule only makes reference to the Damage Resistance Test.

Yeah. I found the post. It's here. I think I was corrected back then too but I forgot about it.OK. I'll correct the above post to be... well... correct.

when the spirit attacks you are you allowed to add combat pool even if you use full defense option?

full defense is fairly useless without combat pool. so, yes.