While waiting for someone over here to chime in. 

As I understand linking G+ and YouTube broadcasts, you can only link the YouTube channel that is on the same Google account as G+ (same email). If your YouTube channel is on a different Google account thank your G+ profile (page) you will have to do it in a few extra steps.

See this page: http://support.google.com/youtube/bin/support.google.com/youtube/bin/answer.py?hl=en&answer=2589825 

CaptRob

YouTube Forum TC