Ax 2012 has a complex Address when compared to the previous versions of Ax.
In this address is not directly linked to the Customer or Vendor directly.
Customer or Vendor has Party which is linked to the DirParty.
DirParty Contains the Primary postal address reference to Logistics Location RecId which is reflected in LogisticsPostalAddress.
In short Dirparty contains the value of Location for searching address in LogisticsPostalAddress.