dunning letter

hi experts,

iam asked to modify one standard sapscript and respective print program of dunning letter , for fi module. for tcode f150. original object is displaying dunning letter output for each customer. when i copied the same object and tried to execute, output is nil. i activated each and every include program etc, but in vain. according to FI consultant they dont maintain application in NACE. so i dnt know how to interlink print program and sapscript, in the original print program form name is not mentioned, i dnt know how the output is displayed in the form of sapscript.

my requirement is as follows

The customer is sent the gentle reminder letter for the out standing balances to be received by them. When ever the dunning program is run based on the dunning procedure assigned in the customer master and the level in the customer master, F150 program should be able to print the dunning letter for the customer correspondence.

regards

maaya