Equipment Number in COPA from Sales Order

Hello COPA Experts,

We are in service industry where we  have requirement to tag all our revenues to Equipment serial number. The equipment number is maintained in Sales order- Extras- Technical Objects tab. Now my requirement is to get this equipment information to COPA at the time of billing for reporting.  I am trying to write an enhancement for deriving this information from SER02  and  OBJK tables. Any pointers on how to get this information to COPA.

Thanks in advance

Best Regards,

RK