SSRS R2 log in after fresh installation

today, I just installed a fresh copy of SSRS R2 and found a serious problem when I tried to login to Report Manager, it kept telling me

User does not have required permissions. Verify that sufficient permissions have been granted and Windows User Account Control (UAC) restrictions have been addressed

After a few googling, I've found a few useful tricks

1. official comments from MSDN, seems I am not the sole victim

http://connect.microsoft.com/SQLServer/feedback/details/622737/user-does-not-have-required-permissions-verify-that-sufficient-permissions-have-been-granted-and-windows-user-account-control-uac-restrictions-have-been-addressed



2. http://www.soheib.com/technical-knowledge/sql-server-2012-reporting-services-uac-user-access-control/

3. (optional)  http://www.soheib.com/?p=381


Basically, you have to Run your browser as Administrator and the URL has to be Localhost (Can not
be the real server name, don't know)
After get in, in the Site Settings -> security, create another role and assign yourself to sys admin.
Then back to the home page , under folder setting -> security, create a new user and assign content manger to this user.

 All done.

The only problem is you have to use browser under Admin , otherwise, it can not be resolved.