I believe there must be some sort of confusion here. You seem to think that Fiddler is some attack/hack/magical tool. To decrypt SSL traffic with Fiddler you either need to possess the session key or you need to install Fiddler's certificate on the device.
Asking for an attack vector and talking about using Fiddler in the same question sounds silly. You're saying you already have access to the traffic, you're already an MiTM. All you need to do is use the session key and or get the device to trust your fake certificate.
I highly recommend that you read up on the topic.