XML-RPC in wordpress - tag input

I using external app for publishing WP posts above http post request .

This is url:

http://ift.tt/1iacPng

This is code:

<?xml version="1.0" encoding="iso-8859-1"?>
<methodCall>
  <methodName>wp.newPost</methodName>
  <params>
    <param><value>1</value></param>
    <param><value>username</value></param>
    <param><value>pass</value></param>
    <param>
      <value>
        <struct>
          <member><name>post_type</name>
            <value>post</value></member>
                <member><name>post_status</name>
            <value>publish</value></member>
                  <member><name>post_title</name>
            <value>title</value></member>
                  <member><name>post_content</name>
            <value><string>post</string></value></member>
          
<member>
            <name>tags_input</name>
            <value>some tag</value></member>                    
      </struct></value>
    </param>
  </params>
</methodCall>

All works, only tags input no ?

Thanks