Help with showing Payment Entry in Journal Entry's "Connections"

Hi All,

I’ve tried multiple ways of using Document Links to make the related Payment Entries to show up in a Journal Entry “Connections”, just like how a Purchase Invoice works. I was able to get as far as making the attached changes to appear in the Journal Entry, but the button does nothing and won’t reflect any changes.


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I’m sure this functionality would be useful for many companies. Please point me to a right direction (even paid customizations). Thanks!