Tag formatting - cannot get to work

[simoncn]

displayFormat is used to customize UPnP metadata that the server sends to the control point for albums and tracks. When values such as #AudioFormat are used as index values, they are not UPnP metadata but names of UPnP containers.

The UPnP metadata is what you see in the control point when you select anything that isn't an index value (an album, the list of tracks within an album or an individual track).

I understand that the distinction might seem strange but it is the way that UPnP works.