You can't. The "Share" button was actually discontinued by Facebook almost 2 years ago. While it still works in very limited cases, it's not supported by JFBConnect at all. The Like button has similar functionality when combined with the Open Graph tags. The Send button is used to send a private message to other users about the page.
There is no way to change the text of the Send button. The Like button can be set to "Like" or "Recommend" though, but that's it. Facebook limits the control you have over the looks of their buttons to prevent abuses that can happen when their looks are changes too much.
Hope that helps,
Alex
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