Back To My Mac, Can't Wake iMac from Sleep..

Hi,

I have an iMac with Back to my Mac setup and the 'wake for access' turned on. I can access my iMac remotely if it is awake but i can't connect to it if it is asleep. I have a Virgin Media Superhub 2 with an apple airport connected to it via ethernet. That has created my network as I have extended it with an apple Time Capsule and all my devices connect to the apple network.

I don't know if its an apple issue or a Virgin Media issue not allowing me to wake my iMac from sleep remotely.

Hope you can help.

Thanks.