HOWEVER, when I click on the "submit" button and save the new node, the file attachments do NOT appear. Can someone tell me what I'm missing here?
upload.module has the code you'll need to study--specifically, upload_nodeapi and upload_save. Note that saving file associations is limited by a permission. The key question to consider is, what does upload do with a *new* node? In this case, any files associated with a node are those that were just uploaded. // New file upload elseif (strpos($file->fid, 'upload') !== FALSE) { This won't help you, as your files array doesn't contain this marker. Consider instead: elseif ($node->old_vid && is_numeric($fid)) { You could consider tricking upload.module into doing the handling by setting an old_vid. Or else just write your own handling based on upload_save.