The FieldRenderer Control (Sitecore.Web.UI.WebControls.FieldRenderer) has a method called OverrideFieldValue that takes a string and is supposed to be shown instead of the real fields value, but it doesn't work.
It seems a fix would be to add in a new pipline that accounts for this preset value.
Here's the code:
public class GetOverriddenFieldValue
public void Process(RenderFieldArgs args)
args.Result.FirstPart = args.FieldValue;
args.Result.FirstPart = args.Item[args.FieldName];
You then need to drop this in the Pipline in the web.config file so that we can modify the value on the way out.
Look for the following node:
<processor type="Sitecore.Pipelines.RenderField.AddBeforeAndAfterValues, Sitecore.Kernel" />
Now add the following above that:
<processor type="Your.Namespace.GetOverriddenFieldValue, Your.Assembly" />
The bug has been logged with Sitecore so hopefully they release an official patch.