We're trying to start a downstream build which expects "UserName" and "UserPassword" as parameters.

```
withCredentials([usernamePassword(
        credentialsId: params.deployCredentialsId,
        usernameVariable: 'MY_USER',
        passwordVariable: 'MY_PASS',
)]) {

    build(job: "deploy/nightly",
        parameters: [stringParam(name: "UserName", value: MY_USER), password(name: "UserPassword", value: MY_PASS),
        ... more parameters
    )
}

```

but the downstream job never sees the UserName / UserPassword parameters. Is there a bug in the above definition, or should I look at the downstream job?