Pin to taskbar works only for the Writer module. For all the other modules the option “Pin to taskbar” is not available on the contextual menu,
Depending on the ‘mode’ that you have logged in as, as of 2013-12-08(Today) LO 4.1.1 has the ability to pin the LibreOffice main start tool to the taskbar. go to Start > All Programs > LibreOffice 4.1 > LibreOfice. Hightlight LibreOffice, right click, see drop down menu, highlight ‘pin to taskbar’, left click. Should now be applied.
Libre Office is now updated to 5.1.0 (called Fresh). LO 4.1 is obsoleted with the release of 5.1 , but still supported with version 5.0.4 ~R