Elektor Formant Modular

I want to midify my elektor formant, I have a doepfer mcv4 and the v/oct works great but the 
gate doesn`t. I guess the doefer has a 12v gate and the elektor 15v or something like that. 
How should I go if I want to convert the 12v to 15v signal? Or is there another answer to this?

-Wille