Generic Delta issue

Hi experts,

I have a problem with generic extractor ( DFKKREP06 table ).

I tested two types of delta but no success. In first case I used the delta field CPUDT (DATS8) of table and the Delta-Relevant Field calendar day, new records was created in the table but delta not considered news records (RSA7). In a second case, I used the field CPUTM(TIMS6) with the Delta-Relevant Field numerical pointer, but not considered new records also.

Is it a problem of system ? I must use a FM with this two fields ? Please can anybody help me ?