Re: [xwiki-users] Velocity script objects mapping to XWiki API ?

I have read http://www.xwiki.org/xwiki/bin/view/DevGuide/Scripting but I can't seem to find how the XWiki API interface is mapped to Velocity "objects". - I understand that $doc refers to the current document ("put" in the Velocity "context") - $xwiki refers to the current xwiki object etc. but I do not understand how to access the other members of the API interface, namely: (from http://build.xpertnet.biz/doc/api/com/xpn/xwiki/api/Api.html ) AdWordsPluginApi, AlexaPluginApi, Attachment, CalendarPluginApi, Element, FeedPluginApi, FlickrPluginApi, GooglePluginApi, GraphVizPluginApi, IPResolverPluginApi, LDAPPluginApi, MailPluginApi, TerraServerPluginApi, User Any pointer would be appreciated e.g. the source file name where "User" is "put" in the Velocity context as example.