Hi there,
Version 1.4.2 of the jQuery library was recently released and it takes some time before the VS doc file becomes available. You can find the 1.4.1 version here:
http://www.asp.net/ajaxlibrary/cdn.ashx
Most of the times, VS will figure out the doc file based on the script files you're referencing. In a JavaScript file it makes sense. VS doesn't know where this file is going to be used, and thus doesn't know what other script files are available. Adding an XML doc reference fixes the problem and brings the documentation in the referenced file in scope.
You may want to up upgrade from beta 2 to the RC version.
Cheers,
Imar