tcl xml-rpc post over http

set getchal "<?xml version=\"1.0\"?>
<methodCall>
<methodName>LJ.XMLRPC.getchallenge</methodName>
<params>
<param>
<value><struct>
<member><name>username</name><value><string>$::ljname</string></value></member>
<member><name>password</name><value><string>$::ljpswd</string></value></member>
</struct></value>
</param>
</params>
</methodCall>"

set getchallenge [http::geturl http://www.livejournal.com/interface/xmlrpc -query $getchal -type "text/xml" ]
set mychal [http::meta $getchallenge]  # also tried with http::status, no joy either way
set doc [dom parse $mychal]
set root [$mychal documentElement]
set nodeList [$root selectNodes {descendant::a}]
set chalvar {}

foreach node $nodeList {
        set attList [$node attributes *]
        foreach attribute $attList {
            if {[string tolower $attribute] == "c0:"} {
                set mychal [$node getAttribute $attribute]
                break
            }
        }
    }