[NTG-context] url with umlaut

The following link \goto{ http://brunelleschi.imss.fi.it/galileopalazzostrozzi/object/RegiomontanusJohannesMullerVonKönigsbergAstrolabe.html}[url(http://brunelleschi.imss.fi.it/galileopalazzostrozzi/object/RegiomontanusJohannesMullerVonKönigsbergAstrolabe.html)] is broken because of the umlaut in the URL. Is some way around it so that the link works? I am using the latest beta standalone. Alan