The file names will be stored in the database table.
You can create a column in the users table to store the file name, then when running the security assist wizard, on the manage pages tab, go to the configure field settings section, and set the file name column to display as a hidden element in the forms.
you probably dont want to include that column in the registration page, only include it in the user update page.
after the pages are created, you will need to add a file field, and the File Upload behavior.
place your cursor next to the hidden element in design view, then go to Inssert -> Forms -> File Fiield to add the file browse field
Go to WebAssist -> File Manipulation -> Upload file.
In the upload settings, select the File Field from the list, on the second step, click the lightning bolt next to Default File Name and select the Hidden Element
after the upload behavior is added, edit the update behavior. For the file column, click the lightning bolt and expand the W Uploaded Files (Files Field Name) binding group, and select the Server File Name binding.