Hi Suresh,
Without FI-TV integrated with Payroll it will not happen automatically, that is why I wrote about manual month-end booking. If you have SAP Payroll and want per-diem as part of salary calculation consider implementing Travel expenses.
Also I do not know how many countries are in your scope, but per-diem logic can be quite complicated and not always possible to capture with time reporting, because can depend on a number of over night stays plus when trip started and when ended and sometime half-rate per-diem can be applicable. Besides per-diem can be dependent on location, so that is yet another variable to consider and that is not native for time reporting.
Also you will be forcing users to fill in Attendance type as mandatory field, but not every one is traveling, so it will complicate time reporting for everyone and not just for those traveling.
Thank you,
Paulo