Extract last date from DSO - Number ID through ABAP

Hi everyone.

I want to delete some records that i dont want to write to DSO through ABAP routine (transformation or DTP). For example, I am reading a number id and a date (yyyymmdd), but for that number I have many dates, and I wanna store the maximun date from all of them. For example:

ID Date

111 20111020

222 20111021

333 20111025

444 20111105

555 20111102

In DSO i want to store '444 20111105'. i tried this with a delta extraction , but the DSO receive any record. It seems the transformation read the DSO at random.

Appriciate your response

Thanks

Ignacio