[xwiki-users] getDocumentAsAuthor doesn't work in attempt to read a page from velocity

Hi! I'm trying to develop a simple script for followng scenario: - Registered User receives an "access code" to the restricted Space - User fills in "access code" and access is granted to him. Following test code is used for tests now (no codes involved yet):   {{velocity}} #set ($mydoc = $xwiki.getDocumentAsAuthor("Week1.WebPreferences")) #set ($rightsObject = $mydoc.newObject("XWiki.XWikiGlobalRights")) ## Set the values of the fields #set ($result1 = $rightsObject.set("groups", "XWiki.XWikiAdminGroup")) #set ($result2 = $rightsObject.set("levels", "view,comment,edit")) #set ($result3 = $rightsObject.set("users", "$xcontext.getUser()")) #set ($result4 = $rightsObject.set("allow", 1)) $mydoc.save() {{velocity}} The problem is: it works only if user alredy has access rights to the Week1.WebPreferences, if not (as desired by scenario) #set ($mydoc = $xwiki.getDocumentAsAuthor("Week1.WebPreferences")) gives Access denied error. The page with this velocity scripting is saved with programming rights user. What is wrong? I'd highly appreciate if anyone point the direction :-) Kind regards, Dmitry