As you mentioned, the Share button has been deprecated by Facebook. See the top of the page below:
developers.facebook.com/docs/share/
Additionally, there is a section "Using Facebook Share on a Facebook-enabled Website" which recommend using the Like button if you are using the 'new' Javascript library (see below).
While we agree that the discontinued Share button does have some nice features, it relies on the old (circa 2008) version of Facebook's Javascript library. That library was replaced in early 2011, and the new library is required for many new features, such as authentication, Open Graph, Facebook Page integration, Requests, and many other things that JFBConnect supports. It is impossible to use the old library and new library on the page at the same time.
We have no plans to implement the Share button. It's likely that Facebook will discontinue the Share button at some point in the future, and if something breaks, Facebook has stated that they will not fix it. While unfortunate, Facebook changes features constantly. Normally, they improve them, but there are other examples where useful features have been removed. JFBConnect constantly keeps up on these changes and tries to hide all the difficulties of integration from our users. Implementing a deprecated feature is not something that will make things easier for users in the long run.
Hope that helps explain,
Alex
Share on facebook page using current facebook share button
