Add hours to task in project server 2013

Hello,

For integration with a custom application I need to add hours for resources to project server 2013. These hours must be coupled to a (existing)  task (and resource) in project server. Also I need the possibility to delete hours for a specific person per task.

I tried to achieve above with CSOM without succes. When getting the tasks I couldn't add hours. (First created a method that prints the information, but with this I am stuck.)

        private static void GetTasks()
        {
            var projects = projContext.Projects;

            projContext.Load(projects);
            projContext.ExecuteQuery();

            foreach (var project in projects)
            {
                projContext.Load(project.Tasks);
                projContext.ExecuteQuery();

                Console.WriteLine(project.Name);

                foreach (var task in project.Tasks)
                {
                    projContext.Load(task.Assignments);
                    projContext.ExecuteQuery();
                    Console.WriteLine("\t" + task.Name);

                    foreach (var assignment in task.Assignments)
                    {
                        projContext.Load(assignment.Owner, temp => temp.LoginName, temp => temp.Email);
                        projContext.Load(assignment.Resource);
                        projContext.ExecuteQuery();

                        Console.WriteLine("\t\t" + assignment.Owner.Email + " " + assignment.ActualWork);
                    }
                }

                Console.WriteLine("-----");
                Console.WriteLine();
            }
        }

Another option I thought was getting the information from the timesheets, without succes because Timesheet remains null

        private static void GetTimesheets()
        {
            var timesheets = projContext.LoadQuery(projContext.TimeSheetPeriods.IncludeWithDefaultProperties(item => item.TimeSheet));
            projContext.ExecuteQuery();

            foreach (var timePeriod in timesheets)
            {    
                //Option one, Timesheet stays null
                projContext.Load(timePeriod.TimeSheet);
                projContext.ExecuteQuery();

                //Option two, Timesheet stays null
                var timesheet = timePeriod.TimeSheet;
                projContext.Load(timesheet);
                projContext.ExecuteQuery();
            }
        }

Does anyone now how to achieve this using CSOM or PSI? Maybe some examples/references to implement above requirements?

Thanks in advance