[mototom]

You'll probably need to use the Item Bonus adjustment to apply the bonus.

As a feature request, it would be great to a) see the source in the adjustments list when it's populated (if this is how we have to make custom items, it's got to be easier to tell why adjustments are there—possibly even allowing a "sort by source") and b) show the actual source text when viewing the skill instead of a generic "item bonus adjustment" in the breakdown of the bonus.