Newbie, problem updating managed metadata fields using Call Web Service Action

Hi All,

I am using SharePoint 2010.

I have a Document library with one content type from the Content type hub.  The Content type has 4 managed metadata fields.  I want to update those metadata fields.

I am using the Call Web Service Action.

This is the first time I have used this web service and am really a newbie with Nintex - so please bear with me.

I am starting small and trying to update only one of the metadata fields as a test.

My column is called Category Category  (I have looked at the internal name and it is Category_x0200_Category)

I understand I need to update the Taxonomy Note field too - which I think is the field Category Category_0 ( the internal name displayed for that is a GUID h9433f21298d47cdb84111a4e6adb06a)

I have tried a number of options for my SOAP (see below) - this works correctly...

<?xml version="1.0" encoding="utf-8"?>

<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:m="http://schemas.microsoft.com/sharepoint/soap/">

  <soap:Header>

  </soap:Header>

  <soap:Body>

    <m:UpdateListItems>

      <m:listName>{F4492B35-780B-437C-B1F4-0064D1FD3199}</m:listName>

<m:updates>      

          <Batch OnError="Continue" ListVersion="1" ViewName="">

            <Method ID="1" Cmd="Update">

              <Field Name="ID">1877</Field>

               <Field Name="TempWFStatus">

<![CDATA[{WorkflowVariable:Val_UpdateText}]]>

</Field>

          </Method>

</Batch>

</m:updates>

    </m:UpdateListItems>

  </soap:Body>

</soap:Envelope>

If I try and add the following

              <Field Name="Category Category"><![CDATA[{WorkflowVariable:Var_CategoryTxt}]]></Field>

               <Field Name="Category Category_0"><![CDATA[{WorkflowVariable:Var_CategoryText_0}]]></Field>              

OR the following

              <Field Name="Category_x0200_Category"><![CDATA[{WorkflowVariable:Var_CategoryTxt}]]></Field>

               <Field Name="{h9433f21298d47cdb84111a4e6adb06a}"><![CDATA[{WorkflowVariable:Var_CategoryText_0}]]></Field>

I get the error

            <ErrorCode>0x81020014</ErrorCode>

            <ErrorText>One or more field types are not installed properly. Go to the list settings page to delete these fields.</ErrorText>

The columns are coming from the content type and I believe are correct - so I really don't want to delete and re-add.

Could someone please point me in the correct direction.

Thank you.

Catharine