Display GeoString on FR920XT

Hello together, I'm trying to display coordinates as a GeoString on the FR920XT. I'm currently using this method for Fenix and Epix:

var geoString = newPos.toGeoString(Position.GEO_DM);
var first = geoString.find("'");

if(first!=null)
{
latText = geoString.substring(0,first+1);
lonText = geoString.substring(first+1,geoString.length());
}

This method works on both devices. But on the FR920XT the strings are not displayed. I think it has something to do with characters that can't be displayed. Does anybody know a workaround for this problem? Thanks in advance.

/Romano