[JDEV] jabber:iq:private?

[zak sy]

hello,

i have a question about jabber:iq:private.  does this feature's availability 
vary from server to server?  i would like to use it to save client 
preferences, but if it's not consistently available, i'm not sure what use it 
really has.  anyway here is what happens when i try to retrieve private data 
and when i try to save it.  any help would be great.

thanks, zak.

RETRIEVE:

 <iq id="P10003" type="get">
     <query xmlns="jabber:iq:private">
            <gif-prefs xmlns="gif:prefs" />
      </query>
</iq>

<iq id="P10003" type="error" from="zds at jabber.com/test" 
to="zds at jabber.com/test">
     <query xmlns="jabber:iq:private">
            <gif-prefs xmlns="gif:prefs" />
     </query>
     <error code="500">Internal Server Error</error>
</iq>

SAVE:

<iq id="T10004" type="set">
     <query xmlns="jabber:iq:private">
            <gif-prefs xmlns="gif:prefs" conv_timeout="20" />
     </query>
</iq>

i get this:

<iq id="T10004" type="error" from="zds at jabber.com/test" 
to="zds at jabber.com/test">
     <query xmlns="jabber:iq:private">
           <gif-prefs xmlns="gif:prefs" conv_timeout="20" />
     </query>
     <error code="503">Service Unavailable</error>
</iq>