There is a link to a rudimentary map on This page
. It seemed to have some sort of coords on it, but it didn't mean anything to me. Have you looked at it?
There is also video about looking for ShiShi Here
. I couldn't watch it because my new computer needs to have flash installed (maybe) but it might spark a memory for you.
I also found a reference on the net to N6.4, W5.5...not sure if that helps either.
I found these instructions
Shishi is north of Maar Gan.
If you follow the Foyoda Bani-dad northwest, the entrance will appear
directly in front of you.
in this walkthrough Here