how can I display the filename in modify form


I have a form with Vault,where I submit a new form ,there is not any problem,but when I modify the form,How can I display the file name exsits in server-side in the Vault? of course,I can got the file name in the form,is there any way to add the file name in the Vault? such as
vault.addExsitsFile(filename),It will display like the file has been uploaded.

you can return 100% from the server and then the control will display the file as uploaded.