How to customize Confirm Receipt PO Notification in redwood

Summary:

I need to add one standard invoice field in this email notification. This email is in redwood template, I am trying to get sample xml from Data model, but data was not filtering even though passing PO number, po header id, requester id. (FYI..I have customized the report and copied the data model to custom folder as well.)

Can some one suggest how get sample xml data from DM and how to customize the template?

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