Ruling Absol Prime and Ampharos PT..what would happen if?

[Emperor_Gaius]

What would happen if I have Absol prime active and Ampharos PT benched..and my opponent plays Uxie or another pokemon with "comes into play" pokepower? Would Absol activate, place damage, and then Ampharos PT prevent them from using set-up? or would the damage be placed After they choose to set-up?

http://pokebeach.com/scans/platinum/1-ampharos.jpg

http://pokebeach.com/scans/legends-awakened/43-uxie.jpg

http://pokebeach.com/scans/japanese/lost-link/thumbnails/absol.gif
No english Scan available: Pokebeach translation:

Absol (Prime) - Darkness - HP80
Basic Pokemon

Poke-Body: Eye of Disaster
As long as this Pokemon is your Active Pokemon, whenever your opponent plays a Basic Pokemon from his or her hand onto the Bench, place 2 damage counters on that Pokemon.

[D][C] Bloody Claw: 70 damage. Place 1 Pokemon card from your hand in the Lost Zone. If you can’t place a Pokemon card in your Lost Zone, this attack fails.

Weakness: Fighting (x2)
Resistance: Psychic (-20)
Retreat: 1

 

[BoDragon]

Uxie, when played from a player's hand, will take 2 damage counters. Having damage counters, it would be unable to use its Set Up Poké-Power.

 

[DNA]

To expand on that:
Mandatory effects, such as Eye of Disaster, always take place before effects where you choose whether or not to activate them, such as Set Up (you are choosing to use Set Up Poke-Power, but Eye of Disaster is always on).