Converting documents to CS3 [JS]

Question

I need to ensure that all documents that my CS3 server sees, ends up as CS3 documents. Thus I've written a small prototype script which I expect should convert all documents to CS3 .indd files:
var dir = new Folder("/spool/");
var a = dir.getFiles("cs2*.indd");
for(i = app.documents.length-1; 0 <= i; i--)
app.documents[i-1].close();
for(i = 0; i < a.length; i++) {
var f = File(a[i]);
var doc = app.open(f);
doc = doc.save(new File("/spool/cs3_" +(i+1) + ".indd"), false, "", true);
if (doc)
doc.close();
However, after letting extendScript toolkit chew on this for a while, my InDesign CS3 still shows the document as a converted CS2 document when opening the newly saved version.
What am I doing wrong?

Answer 1

I'm looking for a method to convert a huge batch of CS2 files to 'real' CS3 files too.
Anyone an idea to get this script running like expected?