SSRS 2014 invalid namespace - sql-server

Question

I am trying to set up forms authentication on Reporting Server 2014. So far I was able to get rid of most of the errors but when trying to log in on reportserver/logon.aspx I get the following error:
An error occurred while attempting to get the ReportServer Url. Invalid namespace
I applied the following in web.config:
<add key="ReportServer" value="localhost"/>
<add key="ReportServerInstance" value="RS_SKOREPORTS"/>
The following is from my reportingservices.mof:
#pragma namespace ("\\\\.\\root\\Microsoft\\SqlServer\\ReportServer\\RS_SKOREPORTS\\V12")
I've tried several things like removing the RS_ prefix but the error remains.
EDIT:
Ok, I have come to the point where I know what's wrong by debugging everything, I just don't know how to fix it. My wmiNamespace string is adjusted for report server 2014 as follows: private const string wmiNamespace = #"\\{0}\root\Microsoft\SqlServer\ReportServer\RS_{1}\v12";
The weird thing is that when I debug the login process and put a watch on fullWmiNamespace the value it returns is:
"\\\\localhost\\root\\Microsoft\\SqlServer\\ReportServer\\RS_SKOREPORTS\\v10"
It looks like report server ignores the changes I made in AuthenticationUtilities.cs and just uses the unmodified version.

Answer 1

Fixed by hardcoding the wmiNamespace string. For some reason the FullWmiNamespace string didn't format the string properly..