LiveJournal xmlrpc date out of order option

I am having an issue adding posts to LiveJournal via the xmlrpc api they provide. I want to add entries older than what I have listed on LiveJournal already. But I get a response saying:

"You have an entry which was posted at 2009-09-06 18:32, b开发者_运维知识库ut you're trying to post an entry before this. Please check the date and time of both entries. If the other entry is set in the future on purpose, edit that entry to use the "Date Out of Order" option. Otherwise, use the "Date Out of Order" option for this entry instead."

I haven't found an argument for the "Date Out of Order" option using the LJ.XMLRPC.postevent method. Any help would be highly appreciated.

In the props argument to postevent, you need to set opt_backdated to true. (See this for the documentation as to what can go in props.)

edit: Here's the XML from the lj_dev entry to which I linked in my comment:

<methodCall>
    <methodName>server.method</methodName>
    <params>
        <param>
            <value><struct>
                <member>
                    <name>event</name>
                    <value><string>the message body</string></value>
                </member>
                <member>
                    <name>props</name>
                    <value><struct>
                        <member>
                            <name>current_music</name>
                            <value><string>football game</string></value>
                        </member>
                    </struct></value>
                </member>
            </struct></value>
        </param>
    </params>
</methodCall>