It seems I actually solved the problem by adjusting another script found here:
http://jsid.blogspot.dk/2006/03/replacing-links.html
//Description: Replace images with prefix to another language
/*
Existing images have the prefix "DK"; New have the prefix "SE"
*/
myDoc = app.activeDocument;
myLinks = myDoc.links;
for (j = myLinks.length - 1; j >= 0; j--) {
myName = myLinks[j].filePath;
myNewName = myName.split("DK").join("SE");
if (myName != myNewName) {
// Originale images have the prefix "DK"
myNewImageFile = File(myNewName);
if (!myNewImageFile.exists) {
alert ("Can't find file: " + myNewName);
continue;
}
myLinks[j].relink(myNewImageFile);
myLinks[j].update();
}
}
Hope others can find use of it.