SharePoint Clear SPFieldChoice using Web Services

I'm trying to clear the selection of a SPFieldChoice using Web Services. I'm currently creating a batch XML then using the UpdateListItems method while passing in an empty value.

This has not been updating the list however so I would appreciate any guidance.

The following is my web service call:

<Batch OnError="Continue" Lis开发者_JAVA百科tVersion="1">
    <Method ID="1" Cmd="Update">
        <Field Name="ID">102</Field>
        <Field Name="Resolved_x0020_Status"></Field>
    </Method>
</Batch>

Thank you.