In 8.4 there is a folder called CS7 Gateways and under Bin folder a file called cs7g.ini, in that you have to add the following lines for that datasource under [DataBases] section
annual_plan_pub=;LOCAL;OL;Provider=SQLOLEDB;Driver=SQL Server;UID=username;PWD=password;SERVER=servername;DATABASE=annual_plan_pub