I had a quick peruse of the data sheet for the aduc834 part (which I use) and from that you can only choose between internal OR external code at reset (/EA). Therefore I would say that paulmon will not work the way you would wish on this part. You can use the external ram as xdata but not as code store.

The only way I can see you getting paulmon to work is if you have an external eprom that has the paulmon code
and holding /EA low on reset. The datasheet notes that you cannot change /EA on the fly as it is used for the special debug interface.

To test the ram as you currently have it configured you can use paulmon to modify locations as xdata just to confirm you have it wired correctly.