Hi there – this theme comes with custom icons for Facebook, Twitter, Pinterest, and email, but not YouTube. If you made a matching icon in a graphics program, you could try adding it via a text or image widget, as the first widget in the sidebar so it would display just below the other buttons.
p.s. In future, please start a new thread rather than adding to an old one – this thread is nearly four years old and it’s by chance that I spotted your reply here. Since your site has a Premium/Business plan, you’re also entitled to live-chat and email support, accessible here: