Import US Per Diems/Flat Rates

Hi All,

import the relevant per diems for settling travel expenses,for this in the PREP t-code how to import the per-diem rates.I tried with performance assistence,but what happining is region and country is displaying but the dates and perdiem rates not importing and updating to the corresponding table V_T70U

can you please tell me what is the procedure and how to solve this solution....