Implementing Single Sign-On from .NET Application to SAP System, using SAP.NET Connector 3.0

We are trying to use SAP.NET NCo 3.0 to implement single sign on from .net application to SAP System. In the configuration set up method we are fetching user name and password along with other configuration information from configuration file. E.g. -

RfcConfigParameters rfcConfig = new RfcConfigParameters();            rfcConfig.Add(RfcConfigParameters.User, ConfigurationSettings.AppSettings["SAP_USRNAME"]);            rfcConfig.Add(RfcConfigParameters.Password, ConfigurationSettings.AppSettings["SAP_PWD"]);            rfcConfig.Add(RfcConfigParameters.Client, ConfigurationSettings.AppSettings["SAP_CLIENT"]);

......and so on for other parameters

We are looking for a way that we can implement SSO with windows authentication where will ne NO need to pass user id and password explicitly. We also have SNC configuration and other required file available with us.

Any relevant code snippet or pointer addressing this will be of great help.

Thanks in advance