SAP AFP file generation

Hi All,

We have a requirement to combine monthly invoice prints into a single AFP file separated by NOP records. Looking for a solution to achieve the following.

1.  Combine monthly invoice prints into a single  AFP file

2.  Insert NOP and PTX records into the AFP file

3. The NOP and PTX records fields need to be filled with data from invoices.  

PS: We were able to generate SAPGOF (OTF) format files from the spool

Any pointers to achieve these requirements will be appreciated.

Thanks

Sanu