Chance of hitting twice?

Simple question.

Is it possible to give a weapon an attribute that makes it SOMETIMES possible (as in there's a chance but it's not guaranteed) to hit with a normal attack multiple times?

I see two available "attack twice" type effects in the features window that don't quite accomplish what I want: "Attack Times+" in the Attack tab and "Action Times+" in the Other tab.

While Attack Times+ causes the normal attack to be used multiple times, it is a constant and not a percentage chance. On the other hand, Action Times+ DOES give a percentage chance value, but it applies to actual actions taken in battle and not times a normal attack is done.

Am I missing something? Or is this impossible?

You'll probably have to script it.  The only other way I can see the ability to do it is to make it a State of some sort that gives you a chance of being inflicted on the user...  And once it is inflicted (via % chance), they get a second attack for a single turn.

You might be able to fudge it some just based on altering hit rates of weapons or other such things...  But, I don't see a way to just flat out do what you're asking.