Invoice output to be added as an attachment in the same invoice

Hi All,

We are using attachment functionality in R/3 System & we have a requirement that the output associated to that invoice should be attached to the same invoice as a PDF format, can this be achieved in simpler ways.

I am looking more at standard ways or with minimal developments, below is the logic which am planning but it is complex

1. PDF conversion to be adopted, but not sure on how it works on batch job ( if this is possible, please let me know)
2. Populating the output in an application layer as a PDF by batch job using VF31 transaction ( not clear on the way the naming convention that can be made on such things & hence presume for naming convention atleast i need to go for custom development).
3. I was indicating about naming convention in the earlier step which will be useful for me when i create a z-program that will take the file name & opens the invoice in VF02 & take that PDF for attaching it.

if we have any other alternatives, please let me know.

Regards

Ilango