Updating custom column in Existing workitem after Refresh click in SBWP

Hi Experts,

Scenario:

After the PO, the invoice receipt from vendor  is scanned to PDF. In OAWD transaction user as below they provide the description.

A work item comes to SBWP for task TS000007869(standard) for the corresponding Invoice. The description that we provide in OAWD comes as a title in inbox. Business Object used : IMAGE (has no link with PO),

So I am thinking if we ask client to provide PO no. in format::  <Description>_ <PO no>    , then we can extract the PO from the description and then corresponding GR is weather made or not.

Requirement :

Client wants to add another column to that SBWP inbox which will notify them that weather GR for for corresponding PO is made or not by some status sign.

Problems :

1. BO (IMAGE) has no link with PO as its only processing the scanned PDF.
2. No idea for situation where after the creation of work item in SBWP if any dynamic value can be updated or not in the custom column, (i.e at the time work item creation if GR is not made and say after 2 hrs GR is made, so when click REFRESH button in SBWP the new  column should be updated with some sign)

Hope you experts got my issue nd kindly provide me some suggestions.

Revert for any clarifications.

Thanks.