Hi Pavan,
Easiest way to get this infromation without reading the Livecache would be is to create a ODL for the locations for which you want this report to work and for every ODL, there is an underlying DB table that gets generated and read the data from there. These DB table follow the name /1RII/<ODLNAME>. SO, for example if the ODL Name is ZDOCUMENTS, then the DB table name would be /1RII/ZDOCUMENTS.
As far as the transaction //AC03 is concerned, system calls the function module /SAPAPO/AVAIL_CHECK_CONTROLLER to display the data.
Hope this helps
Babu Kilari