How to copy sap standatd report to add fields and to make it work

Hi experts,
    Can you tell me how to copy the sap standard report to add fields.
I copied regular way including all includes also, but the porgram not activated and also every field started with %
exp : data %dtab type standard table of /1BCDWB/IQ000000008078 with header line.


Local object yes.
I realise you're not an abaper, but if you got one in, he could simply create a subclass of /SAPPSSRM/CL_FY_NUMBER  (assuming it's not been made final) and override only the method that needs changing.  ( if it is final, then you have to use composition, but again, that's pretty straight forward ).  The point is, that copy a class rarely, if ever, needs to be done.  That's one of the major points about using classes.  If you use subclassing or composition, only small amounts of code need to be copied - which means if SAP change other bits in a new release, you automatically get them, thereby reducing the risk of an upgrade mucking up your cloned class.
I'd be extremely nervous about having any code that had been implemented by a non-developer, being put into productive use.