Adding extra name space in Receiver file

Hi ,

I am working on Proxy  to File scenario,I am having trouble in adding name space in the header.

Receiver side they are expecting the XML in the below format.

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

<object_interface xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<employee>

<emp_identifier>8278</emp_identifier>

<emp_sap_id>121</emp_sap_id>

<emp_first_name>Jennifer</emp_first_name>

<emp_last_name></emp_last_name>

<emp_address1></emp_address1>

<emp_address_line2></emp_address_line2>

<emp_address2></emp_address2>

<emp_province></emp_province>

<emp_address3></emp_address3>

<emp_home_phone>21212221</emp_home_phone>

<emp_team>2121</emp_team>

</employee>

</object_interface>

I need to add xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance in one of the fields,can any body help me in this issue.

Thanks