How to see the DMS document number in PO / PR?

Dear experts,

I am using DMS. I have created a document in DMS and I have linked it to the PR & PO line items. Till it is fine.

But I am not able to find out this document in PR / PO. Can some one help me how can I find the document number in PR / PO??

Thanks in advance.

Regards,

Praveen