Provider-specific signature in prescriptions

I’m trying to enable each provider’s signature to appear in prescriptions, when using “Download (Fax)”. I can get it to work with the same signature for all, but see nothing otherwise, presumably because I don’t understand the syntax.

sites/default/config.php contains the following:

$GLOBALS[‘oer_config’][‘prescriptions’][‘sig_pic’] = “sig.png”;

“This filename may include the string “{userid}” to indicate the numeric ID of the user, so that prescriptions can print with the correct provider’s signature if you have multiple providers.”

And this is in place:
interface/pic/sig.png

For a user with id of 1, what would the above look like please? Like the following?:

$GLOBALS[‘oer_config’][‘prescriptions’][‘sig_pic’] = “sig{userid}.png”;

interface/pic/sig1.png

Thanks

The filename requires the username, not the user id as described in the config file.