Password Variable

I have a SSH entry and a credential one linked to it. I've enabled "Allow password on a variable" on both of them and 'm trying to open PLSQL Developer using a command-line I've setup with the following arguments:

userid=$USERNAME$/$PASSWORD$@$PARENT_NAME$

The tool opens, but the authentication fails.

To debug what was going on, I created a bat file to echo the variables and, as you can see, the only one that is not working is the $PASSWORD$...


Do I have to enable something else?

OBS.: My user is Administrator.