how to use access token to create a new user account using google provisioning api in .net

Question

I am trying to create a dektop application to create new user account into particular user group using Provisioning API of google.

I am using some >Net libraries in my code , here is how my code looks like.

string token = GetNewAuthenticationToken("domain.name", "adminEmail", "adminPassword");
AppsService service = new AppsService("domain.name", token);
service.CreateUser("usernametest", "userfirstname", "userlastname","userpasswordtest12345");

But I am getting this error, Execution of request failed: https://apps-apis.google.com/a/feeds/domain.name/user/2.0

I know it has something to do with token I am getting, can anybody have any idea on how to pass the token with service.createuser method?

And also what is use of that client id and client secret code which is generated while registering app on google.