Send invitation to any user of google chats (is it possible?)

I try to realize simple code on perl which should just get/send messages from/to gtalk accounts. I use Net::XMPP::*

modules. All works just fine for users, who are my friends (in my "buddy" list). But i can't send message to unknown user. I know, that for this case i must send an invitation first, but

Net::XMPP::* don't provide this possibility. There is only one way to invite person - construct my own xml according

to "XEP-0155 Stanza Session Negotiation" protocol. But this doesn't work correct. When i send xml to server, it

returns error "service-unavailable".

I send:

<message to='[email protected]'>
 <sxde xmlns='http://jabber.org/protocol/sxde'
   xmlns:sxde='http://jabber.org/protocol/sxde#metadata'
   session='0AEF4278DC4B6577'
   id='b'>
  <negotiation>
    <invitation>
      <feature var='http://jabber.org/protocol/whiteboard' />
    </invitation>
  </negotiation>
 </sxde>
</message>

before my message.

ANSWER:

<message from='' to='[email protected]/TALKCDDCCE63' type='error'>
  <sxde id='b' session='0AEF4278DC4B6577' xmlns='http://jabber.org/protocol/sxde' xmlns:sxde='http://jabber.org/protocol/sxde#metadata'>
    <negotiation>
      <invitation>
        <feature var='http://jabber.org/protocol/whiteboard'/>
      </invitation>
    </negotiation>
  </sxde>
<nos:x value='disabled' xmlns:nos='google:nosave'/>
<arc:record otr='false' xmlns:arc='http://jabber.org/protocol/archive'/>
<error code='503' type='cancel'>
    <service-unavailable xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
</error>
</message>

Maybe i lost smth or should send another info before (or after..) ?

Or maybe there are another way to send message without any invitation?

Thanks in advance

Solution

First You need to authenticate your jid, then you could send message stanza to xmpp server. Subscription required only for presence notifications.

<message to='[email protected]/TALKCDDCCE63' type='chat' xmlns='jabber:client'>
<body>TEST MESSAGE</body>
</message>