Most journal specific features can be set via "lj-headers" in the body of your message. The lj-headers should be at the top of your message, separated by a newline. All lj-headers are completely optional, and simply override your journal defaults.

Security options are set via the lj-header "lj-security". If the security type specified is unknown, the journal entry defaults to private. If no security is specified, the entry is posted according to your default journal security.