How to design a form to respond to a workflow status of a Custom worklow (not OOB workflow)

The following article describes how to change view of a browser enabled InfoPath form based on the current status of a workflow: Design a form to respond to a workflow status
The article uses an Out-of-the-box (OOB) workflow and its workflow column.

But, I have created a custom workflow using SharePoint Designer (SPD) and according to the some responses to my following post, , the workflow column in a custom workflow cannot be modified to display the values “Approved”, “Rejected” etc.

How can I then change the views of a browser enabled InfoPath form based on the current status of a workflow. I want to display the form as follows:

1. Make it read only once it has been submitted.
2. Make it Green once it has been approved
3. Make it Red if it was rejected

Thanks……..