update:
i've been looking on your suggestions guys and ended using "Office Ribbon Editor" to create the tab. yet i've encountered another problem: (my project is a Macro-Enabled template) when opening the document, a window pops-up and asks to choose the xml expansion pack. it has 2 options "No XML expansion pack" and "Microsoft Actions Pane 3".
the problem is that it pops up every time i open the document. how can i make this disappear?