and the reply:
"Two things. Make sure you are playing the final release that is MSDS.1 (says on title screen when you start game) and not the original release as it has a few bug fixes that might help this work, I only tested with the final .1 version. If you manage to unlock the back alley using the above instructions successfully a strip in the street between the two buildings on the far right will light up when mouse moves over it to select the alley."
I'll add, the game is available on my personal site: www.tempysart.com