[xwiki-users] Not getting logout from xwiki application

i have implemented the single sign on of xwiki with my web application. Basically when i click xwiki hyperlink on my webapplication it takes me to xwiki site hosted on another port without asking the credentials. Behind the scenes it creates an empty user in xwiki databse with no password. Till here its perfect.But when i click on logout on right top of the page it does not do logout. it brings me on the same page.I tried debugging the issue whole day but could not find any concrete finding. when i do the login on xwiki site directly with some created credentials(i mean in giving address in address bar directly)and do the logout it does the log out. I found the major difference is when we do the login manually it sets the username and password in cookies and sets some other stuff too like user principal in request and onlogout it retrieves the same info from cookie and gets successfully logout.But in my case as it creates the empty user i.e with no password it does not set the above stuff in cookie and when i click on logout it stays on the same page.i am not getting how to get thru this. Any help would be highly appreciated.