Bring item table to codeunit Sales-Post+Print

Dear folks, on codeunit Sales-Post+Print I've a code that prints a report automatically when from sales quote you select Print+Register. The code is like this:

SalesShptHeader.RESET ;
SalesShptHeader.SETFILTER("No.",SalesShptHeader."No.") ;
RptNumserie.SETTABLEVIEW(SalesShptHeader) ;
RptNumserie.USEREQUESTFORM := FALSE;
RptNumserie.RUNMODAL ;
CLEAR(RptNumserie) ;

SalesShptHeader = is Sales Shipment Header table
RptNumserie = is the report I want to print

The code runs well but it prints the report always. Now I want that it only prints if one of the items from item table has informed a field. For example is field cap='ser'. But I can't bring me the item table to the codeunit to compare it. How can i do that?.
Thanks.