You need to read both the Data Sheet and the User Manual for the device:

Data Sheet: http://www-us16.semiconductors.com/acrobat/d...932-04.pdf
User Manual: http://www-us16.semiconductors.com/acrobat/u...C932_3.pdf

Fig 1-5 on p19 of the User Manual shows that the AUX RAM actually falls within the 8052 XDATA space;
The general description on p20 says, "'External' Data or Auxiliary RAM. Duplicates the classic 80C51 64KB memory space addressed via the MOVX instruction using the DPTR, R0, or R1. All or part of this space could be implemented on-chip. The P89LPC932 has 512 bytes of on-chip XDATA memory."

Table 5 on p20 of the Data Sheet shows the internal data memory arrangement.