I have a Fighter (Slayer) from Heroes of the Fallen Lands. One of the class features is called Heroic Slayer, and it gives this benefit:
Benefit: You gain a bonus to the damage rolls of weapon attacks. The bonus equals your Dexterity modifier.
At level 1 you also get a power called Power Strike:
Power Strike; Fighter Attack
Encounter; Martial, Weapon
No Action; Special
Trigger: You hit an enemy with a melee basic attack using a weapon.
Effect: The enemy takes 1[W] extra damage from the triggering attack.
Do I add damage equal to my Dex modifier to both the melee basic and Power Strike, so that the total damage from a melee basic with a longsword to which Power Strike is applied is 2d8 + Str + Dex + Dex?