Hi,
Unfortunately it's currently not supported to add a label text to a Marker in TMS WebOSMaps.
This is a limitation of the OpenLayers API which we have no control over.
This is a limitation of the OpenLayers API which we have no control over.
As a workaround you could add a Polygon at the same coordinates of the Marker and use the Polygon.LabelText property to add a label text to the map.