What version of the product are you using?
The dialog in your third image is for the Run entity. In v11.52 there is a hot link at the bottom to bring up the source test case details, which opens another dialog where you would see the custom field added to the test case.
If you are working with an earlier version that doesn't have that feature, then what you would need to do is add a user defined field to the Run entity and programmatically copy the data from the Test case through workflow customization.
The dialog in your third image is for the Run entity. In v11.52 there is a hot link at the bottom to bring up the source test case details, which opens another dialog where you would see the custom field added to the test case.
If you are working with an earlier version that doesn't have that feature, then what you would need to do is add a user defined field to the Run entity and programmatically copy the data from the Test case through workflow customization.
