How do magic weapon special abilities work with the necklace of natural weapons?

By | June 13, 2018

The necklace of natural weapons (Savage Species 58) allows the wearer to have one or more of his natural weapons gain magical enhancement bonuses on attack and damage rolls and allows the wearer to have magic weapon special abilities affect one or more of his natural weapons.

When the magic weapon special ability spell storing (Dungeon Master's Guide 225) (+1 bonus; 0 lbs.) is added to a necklace of natural weapons, does each natural weapon that the necklace affects benefit individually from the magic weapon special ability spell storing?

That is, does the wearer have, effectively, a separate, unique spell storing magic weapon special ability for each natural weapon the necklace affects, allowing the wearer to put, for example, a vampiric touch spell in his necklace's slam's spell storing "chamber" and a combust spell in his necklace's gore's spell storing "chamber"?

Or is but one spell storing "chamber" shared by all the natural weapons: the spell storing weapon special ability holding but one spell, and the wearer able to pick on the fly the natural weapon affected by the spell storing magic weapon special ability? Or is there some other option?

An excellent answer will likewise address weapon special abilities that have limited uses per day (e.g. the magic weapon special ability banishing (Magic Item Compendium 28–9) (+2 bonus; 0 lbs.) that functions 3/day)), using the answer's own ruling or picking whether such uses per day are either per natural weapon affected by the necklace or per necklace.