Plus....on top of that I know the Keil linker has parameters wherein you can specify the areas of address range where XDATA is actually located.

Look specifically at the command line control called XDATA that is described in the Keil Assembler/Utilities manual. (Try section 9 at approximately page 350). In the source code you would place the data variables you wanted to place in the unused on-board XRAM space to be in a particular segment. The XDATA directive then allows you to specify a specific start address for the group of data variables that you placed in this segment. Should work right sweet for your needs.

Michael Karas