Item Journal Posting with Tracking Spec.

Hi,
I need your help with posting Item Journal Lines...
Usually I'm doing this like follows:

ItemJournalLine.INIT;
ItemJournalLine.VALIDATE("Posting Date",WORKDATE);
...
ItemJournalLine.VALIDATE(Quantity,1);
ItemJnlPostLine.RUN(ItemJournalLine);

Post without insert item journal line to the database... but right now I have a problem - how sholud I add support for the Item Tracking Specification?
Create reservation entry for non existing item journal line???