solving passive scalar by user function in AVLFIRE
 

I want define a passive scalar on wall boundary and solve such scalar through defining scalar source term by user function "usepsc.f". (It can be solved in FLUENT by UDF and UDS):

Please give me following help: 1. How to define passive scalar on wall boundary in FIRE?(I tried defining phib(nbfac) to fixed wall in user function, but no effect to scalar) 3. How to define diffusion coefficient by user function to scalar source in FIRE? (I tried defining dif(ncell) in user function, but no effect to scalar)

Best regards,