var myDoc = app.documents.item(0); 
myTopic = myDoc.indexes[0].topics.add("Satzprogramm");    
myTopic.pageReferences.add(app.selection[0]);  
 
 
//Das habe ich schon probiert 
//myTopic.crossReferenceType == CrossReferenceType.SEE; 
 
//myTopic.crossReferences.firstItem().referencedTopic.name = "Indesign"; 

var referencedTopic = _index.topics.add("Indesign"); 
myTopic.crossReferences.add(referencedTopic, CrossReferenceType.SEE); 

var myDoc = app.documents.item(0); 
 
myTopic = myDoc.indexes[0].topics.add("Satzprogramm");    
 
var referencedTopic = myTopic.topics.add("Indesign");  
myTopic.crossReferences.add(referencedTopic,  CrossReferenceType.SEE); 

var myDoc = app.documents.item(0);  
  
myTopic = myDoc.indexes[0].topics.add("Satzprogramm");     
  
var referencedTopic = myDoc.indexes[0].topics.add("Indesign");   
myTopic.crossReferences.add(referencedTopic,   CrossReferenceType.SEE);