Element Resistance and Immunity

I made it so that certain enemies are immune to certain elements. I thought it would be interesting to include and Item that adds a weakness to an element, or all elements. To counteract the effect, maybe as a quest reward or something. But the way I have it set up it doesn't work. Does anyone know how to do this?
Pictures are the setup I currently have.

A server error occurs whenever I try to upload pictures, so for now I'll describe it, and then try again tomorrow to upload it.

I created a state called fire weakness, in the features box I put Element Rate Fire*100. I set the duration to 2 turns, and the Auto removal timing at turn end. I then created an Item called, Super Weakness, and under effects I added the state Fire Weakness. The scope is set to enemy, success 100%. But it does nothing.

Thanks in advance.

Also, side note: Why is it that adding Fire Immunity to an enemy doesn't make them immune to fire based attacks?

The reason it did nothing is because it is as you set it up, you said fire damage * 100%, which is the same as normal damage. To make them weak to an element you have to set the element rate to higher than 100%, as the element rate is multiplied to the damage to get the final damage. That also means any element rate under 100% makes them strong to the element, and element rate 0% makes them take no damage from that element.

Oh, I thought it was +100%, not multiplying to 100% or 1. Can't believe I missed that, thanks, it works now.