a lot of time lookinf for a solution for have more realism in the system of fire engine of the 737..this is the solution that i found:

i have a 737 cockpit (cockpitsonic MIP and OVH) and the pedestal from CP flight,using Magenta software.

with the soft of FSPS (Achilles) now i have a real fire warniong system, using his software of 737 fire system with P. Magenta and cp flight fire system.

these last days Achilles work hard to found and implement the solution for gives more realism to the system, now you can provocate a engine fire, you will see the red lights, and the sounds work, ...with these you can add more true realism to the flight and posible operations and procedures with fire in engines.
look for the software of FSPS (http://www.737ng.gr/) and if you have doubts, contact Achilles for support, is FANTASTIC.
THANKS Achilles for give us with your software more procedures to operate in the cockpits.