AIPerception and AIStimulus strength

Hi, I’m currently using the new detection system. Here is my blueprint :

http://puu.sh/lzu5P/3b19e56323.png

The problem is my strength returned is always -1 (default value). Even if my blueprint works perfectly in game. I use this in my player blueprint :

http://puu.sh/lzuaC/0203404bc9.png

I want to set behavior according to the distance and the strength of the stimulus so all my AI is related to this problem. Do not hesitate to ask me for more details but everything i have created is here. And all my components are correctly setuped.

Regards.