Attachments uploaded on creation of new document with object are not visible

In an AWM application with a content field:

1/ Create a new document but do not save it
2/ Add an image in the wysiwyg field through the upload wysiwyg feature
3/ Save the document

The image will not be visible, although it's in the database.
If you add another image, the first one will appear.

Afte investigation, the upload creates the document with XWD_ELEMENTS=1, but when saving the document with object the XWD_ELEMENTS field is set to 2 (instead of 3). Therefore the attachments are not loading in the loadDocument function.