Lightning Tether as an item skill

I’m trying to add a tether-like spell as an item skill, but can’t seem to make it work. I’m wondering whether is it possible at all, or if I’m merely approaching it the wrong way; I have no modding experience in either GD or TQ, so I might be missing something obvious.

I gather that Lightning Tether is a modifier with its own template, SkillSecondary_Tether, which requires a primary skill for targeting and casting. I tried adding the tether directly to an item, along with an itemSkillAutoController, to no avail. This leads to my first question:

  1. Am I correct in the surmise that tethers require a primary skill to trigger, or is there a workaround?

Following my first attempt, I tried granting both a stormbox-like dummy skill and the tether modifier for it. Both the skill and the tether modifier are correctly displayed in the item description. However, only the base skill is casted correctly: the modifier doesn’t apply and no tether appears. I also tried getting a trigger skill to autocast the tether, which made it appear as a “Celestial Power” in the item description, with similar results. “Borrowing” a tethering spell from the skill tree of a pet also didn’t work. So, my second question would be:

  1. Can modifiers be applied to item skills in the first place?

On the subject, I also tried applying a modifier to the inquisitor’s own Lightning Tether. The modifier is displayed correctly in the item description, but is not in fact applied. I take this is also impossible, so that modifiers can’t be applied to modifiers?

Thank you for your help.