PS Query Drilling URL - Attachment URL to URL which is a FTP site, NOT a database table

Is it possible to use a FTP type URL in a drilling URL in a PS Query?  The only way I've had it work and actually produce the document in the FTP site/folder is to use an Query - Drilling URL - Attachment URL- URL Type = External URL.  If I set the URL Type to Internal URL, I get the error message "URL Identifier {URL Name} in request is not of record type".

The problem with using the External URL as the URL Type is that the URL definition contains the user name and password in it.  When you perform an "inspect element" in the Chrome browser, you can see that the User Name and Password is available for anyone to see.  The user name and password will also appear in the browser tab if the target document is not found in the URL site (FTP URL).