send xmlrpc post request via http with tcl client

The Codex page for xmlrpc doesn’t give information on how to send a post request (has everything else, like editing categories, to adding media…but no post request…hello!).
I’d really like to see a sample xml post request, more than anything.

Trying to do that in Xpostulate (tcl/tk blog client), like this:

proc wppost {} {

set content [.txt.txt get 1.0 end]
set escaped [string map {
	"<" "<"
	">" ">"
	\"  "\""
	} $content]
.txt.txt delete 1.0 end
.txt.txt insert insert $escaped

set ptext [.txt.txt get 1.0 {end -1c}]
set time [clock format [clock seconds] -format %G%m%dT%T]

global mypost
set mypost "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
<methodName>metaWeblog.newPost</methodName>
<params>
<param><value><string>MyBlog</string></value></param>
<param><value>$::wpname</value></param>
<param><value><string>$::wppswd</string></value></param>
<param><struct>
<member><name>categories</name><value><array><data><value>$::cats</value></data></array></value></member>
<member><name>description</name><value>$ptext</value></member>
<member><name>title</name><value>$::subject</value></member>
<member><name>dateCreated</name><value><dateTime.iso8601>$time</ dateTime.iso8601></value></member>
</struct>
</param>
<param>
 <value>
  <boolean>1</boolean>
 </value>
</param>
</params>
</methodCall>"

set plength [string length $ptext]

set dopost [http::geturl https://$::wpname.wordpress.com/xmlrpc.php -query $::mypost -type "text/xml" ]
set wpstat [http::status $dopost]
set wpresponse [http::data $dopost]

toplevel .rsp
wm title .rsp "Post Status"

frame .rsp.btns
grid [tk::label .rsp.btns.lbl -text "WP says: $wpstat\nPost length: $plength"]
grid [tk::button .rsp.btns.view -text "View Journal" -command {
    set wpu "https://$::wpname.wordpress.com"
    exec $::brow $wpu &
}]\
[tk::button .rsp.btns.ok -text "DONE" -command {destroy .rsp}]

frame .rsp.txt
text .rsp.txt.t -width 80 -height 20
.rsp.txt.t insert end $wpresponse

pack .rsp.btns -in .rsp -side top -fill x
pack .rsp.txt.t -in .rsp.txt -side top -fill x
pack .rsp.txt -in .rsp -side top -fill x

}

Getting this response:

<?xml version="1.0"?>
<methodResponse>
  <fault>
    <value>
      <struct>
        <member>
          <name>faultCode</name>
          <value><int>-32700</int></value>
        </member>
        <member>
          <name>faultString</name>
          <value><string>parse error. not well formed</string></value>
        </member>
      </struct>
    </value>
  </fault>
</methodResponse>

I am successfully posting to livejournal, dreamwidth, and other Lj clones using the xmlrpc method, but not finding good documentation on the difference between an LJ post and a WP post.
Clearly, some LJ props (current_mood, current_music) are not relevant, etc.
The above xml attempt is based on info from https://msdn.microsoft.com/en-us/library/aa905673.aspx
My LJ+clones procs create different xml, because there are different relevant variables, but otherwise, the procs are basically the same, and functioning for those blogging services.
Any idea where my xml is malformed? (I’ve read over it, and it looks right to me)
Am I missing a relevant or required variable?
Any ideas?

thanks
tony