FM Document From PO

Hi Everyone

I used FMCN + FMCT to update PO documents. It worked correctly. Now, I want to create FM budget document from PO. I used FMN4. But it is creating budget document.How to create fm document from PO. Some PO's document chain is completed. Gr and IR was created. How Can I create fm document for these?

Please advise about this

Thanks