Login form where password field is initially text field

I’m trying to get Kee to autofill a form whose designer had the incredibly bright idea to deliver it as type=“text” and “oninput” turn it into a password field. The user name field next to it is recognized and filled in correctly, but this so-called password field remains blank (even after I type something in it so it becomes type=“password” in the DOM). The “form fields” page in KeePass will not let me change the type of the password field to “text”, delete the predefined password field, or add another (complaining about a reserved placeholder).

I can add another field that matches the one on the page, with a value of “{T-REPLACE-RX:/{PASSWORD}/-/-/}” to get around the reserved placeholder, but that just looks ugly.

Is there a better way?