The healing power enchant (in wotlk 29SP) is not giving my damaging spells any extra damage. Atleast not at lvl10. It is boosting healing spells though. It seems that it still only gives healing power even though the stats indicate spellpower.
I started a shaman, enchanted the 1h heirloom hammer with healing power, using lightning bolt with and without the hammer only gives me the 7 damage from the hammer spellpower. Not the enchant.
EDIT:;
healing wave is getting the extra spellpower. Same testing method