This post is aimed at helping who has never configured the Team Foundation Server and Project Server integration
First of all: do not use NT AUTHORITY\Network Service as a service account.
After this sanity check, the prerequisites: a Team Foundation Server 2010 or above, a Project Server 2007 or 2010, and the Microsoft Team Foundation Server 2010 and Microsoft Project Server Integration Feature Pack (FP for us , it must be installed on the servers)
Then, the configuration. It’s a four steps procedure, from the Visual Studio command prompt.
First: I register the Project Web Access with the Team Foundation Server.
Second: I map the Project Web Access with the Project Collection I need.
Third: I load the field mapping.
Fourth: I map the Project Server’s Enterprise Project to the Team Foundation Server’s Team Project