Populating custom node in a standard object

Hello experts,

I have a custom node in Opportunity BO as follows.

node SegmentCombos[0,n]{

            element ZSLBProdFCItm : LANGUAGEINDEPENDENT_LONG_Description;

        }

I am trying to populate this node in the following way.

var thissegmentsobj : elementsof this.SegmentCombos;

        thissegmentsobj.ZSLBProdFCItm = "Some";

        this.SegmentCombos.Create(thissegmentsobj);

When I activate i get error : Syntax error in run time and ABAP objects.

Anyone faced similar issue?