I'm experimenting with the XML library export, and MPL importing functions. I've created a numerical "album rating" field in MC's library, and importing values from a MPL file works fine. Now i'm looking for a way to clear that field via a MPL import. I've tried various values in the MPL file: when leaving the value empty, MC won't update the field at all. When i'm using "0" (zero), something utterly strange happens: at the first glance, the field seems to be empty in MC. But when creating view schemes based upon the "album rating" field, i get two "Unassigned" entries in the corresponding pane (!). In a exported XML file, the "album rating" field is filled with a "0", instead of being skipped. I've already reported a bug in connection with "0" values of fields, but sadly got no reaction at all from the MC devs.
Anyway, my current question is: how can i clear a numerical field (or other field types) via MPL import?