I have enabled excel upload with the listener, and it actually works fine. I get the data into a collection.
Now what if I want to store the file in the database? It seems that the file is NOT inserted into wwv_flow_files. Also the item that contains the file has no value when the page is submitted with the XLS2COLLECTION button. (If I create another button that also submits the filename is there)..
So it seems that when this feature is enabled the file is deleted from www_flow_files when page processing starts.