MM_EKKO archiving issue

Dear Experts,

      I have a requirement to archive EKKO, EKPO tables. When i tried doing it using MM_EKKO object, im getting error that "Retention period is not maintained". But I have maintained the retention period in SPRO Tx. I have given residence time 1 and residence time 2 as '1' . Though the last changed date is far behind the current date, i'm getting this issue. Please help me out.

Thanks in advance

Regards,

Shanthi