Can't seem to send customdata with Edge (PlayReady)

So i'm trying to play PlayReady content on IE and Edge browsers. Now i'm sending the customdata with the createSession function. (this.keySession = this.player.mediaElement.msKeys.createSession('video/mp4', event.initData, customData);) and this works fine for IE.

But for edge this doesn't seem to work. (For edge i'm using mediaKeys instead of msKeys). Is it because edge doesn't support custom data in PlayReady?