NamedScopes Ninject bindings and async (threading)

My project is structured by services and repositories (all repositories share the db context). In one of my service layers, I have an asynchronous method that writes to the database using a repository. The web request will finish and dispose of the context before this method can get to use it. I tried to understand NamedScopes as stated in this answer. I still can't seem to understand how to implement it. I'll show how my project is structured and hope someone can help me at the code level.

Bindings

    private static void RegisterServices(IKernel kernel)
    {
        //dbcontext
        kernel.Bind<EntityDatabaseContext>().ToMethod(context => new EntityDatabaseContext()).InRequestScope();

        //unit of work
        kernel.Bind<IUnitOfWork>().To<UnitOfWork>().InRequestScope();

        //repositories
        kernel.Bind<IRepository<Account>>().To<Repository<Account>>().InRequestScope();

        //services
        kernel.Bind<IAuthenticationService>().To<AuthenticationService>().InRequestScope();
    }

AuthenticationService uses constructor injection

public AuthenticationService(UnitOfWork unitOfWork, IRepository<Account> accountRepository){}

A method inside my AuthenticationService

    //this is a background process
    public Task SomeMethodAsync(string text)
    {
        //spin it off into a new task
        return Task.Factory.StartNew(() => SomeMethod(text));
    }

SomeMethod makes use of accountRepository. Please tell me if anymore information is needed. Please help me with the threading issue, if NamedScopes is the solution, how do I implement it in my case?

Basically, a background process is being executed and it is using a context that is being disposed of by ninject due to the request scope.