tdom question

I want to extend an xml file:

<ns1:Root xmlns="http://default.com" xmlns:ns1="http://some.otherns.com">
    <ns1:Item>Here be text</ns1:Item>
    <ns1:Item xmlns="">Other text</ns1:Item>
</ns1:Root>

Into:

<ns1:Root xmlns="http://default.com" xmlns:ns1="http://some.otherns.com">
    <ns1:Item>Here be text</ns1:Item>
    <ns1:Item>Other text</ns1:Item>
</ns1:Root>


But best I can do is:

<ns1:Root xmlns="http://default.com" xmlns:ns1="http://some.otherns.com">
    <ns1:Item>Here be text</ns1:Item>
    <ns1:Item xmlns="">Other text</ns1:Item>
</ns1:Root>

With the code below. What would be the proper way to get the desired output (without xmlns="")

package require tdom
set xml  {
<ns1:Root xmlns="http://default.com" xmlns:ns1="http://some.otherns.com">
    <ns1:Item>Here be text</ns1:Item>
</ns1:Root>}

dom parse $xml doc
set root [$doc childNodes]
set item [$root selectNodes //ns1:Item]
set itemLst [$item asList]
lset itemLst end end end "Other text"
puts [[$root appendFromList $itemLst] asXML]