This one appears to be stumping a number of people.

The general use case is to trigger off of a milestone target date in Process Builder, or Workflows, or other Service Cloud processes, or in my situation - creating a Calendar that displays cases with upcoming SLA milestone target dates.

The work around appears to be to populate a custom case field (such as Due_Date__c) and then use that field as the trigger or reference point.

I just don't know how to populate a case's Due_Date__c with the case's SLA Milestone Target Date. I brought this up to Premiere Support and they referred me to here since they confirmed that:

"we cannot achieve this by process. I'm afraid this is also difficult through triggers or flow."

So it looks like this may require some Apex magic. I'm not that familiar with Apex or how to trigger it per se, but I understand basic code syntax. Would someone like to take a crack at solving how to update a custom due date field with a case's milestone target date?