If the containing div has its width set to (barely) contain the share buttons, and you give it a css property of margin:auto then the buttons should be centred OK (assuming that that div is inside a full-width container).
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.