Set Time Spent and Correction fields as Required Properties

Let me adjust my question based on my recent observation. I see that I can add a "Required Estimates Precondition" to a user Role, for a given work item type. This is what I was looking for, almost. I am unable to set the timing of this to a certain workflow event (as I can with Required Properties). So I don't quite have my solution.

Is there another version of this "Required Estimates Precondition" that exists without the 'precondition' (for all workflow events) limitation?

My thought process is that until the work starts, we really don't have a good sense for the work, so how can I require an estimate when in the NEW state? And further, how can I ask for time spent, until we START WORKING?

thanks

I'm unable to see these as options for a Required Property setting (for any part of a workflow). I'm using v2.0.0.3.

I can see other 'core / built-in' fields such as Due Date or Owned By, so I'm confused why I cannot see these two fields.

My desire is to make these fields required as of a certain point within a workflow. I am familiar with how to set Required Properties within the Team Configuration - Operation Behavior screen.

Do I need to map these as Custom attributes against my custom work item type for some reason? It seems that all custom fields are options for Required Properties within a workflow. This would seem strange to me, but I just need a solution.

Can you help me out?

Thanks much!