Add attributes to a xml root element

I'm developing using SQL Server 2012 express and developer solution.

I need to generate this xml:

<Co BNumber="B001" Username="" Annothation="Nothing">
    <Item PId="57151" IId="005CYEHE19N35B" ILevelId="0" IFlag="20" Time="2014-12-16T14:34:03.743"/>
</Co>

But at this moment I'm generating this:

<Co>
    <Item PId="57151" IId="005CYEHE19N35B" ILevelId="0" IFlag="20" Time="2014-12-16T14:34:03.743" Username="" Source="PLS"/>
</Co>

This is my SQL code:

DECLARE @xml_var XML
SET @xml_var = 
(
    SELECT ID_CODE AS '@PId',
        CODE AS '@IId',
        CODE_LEVEL AS '@ILevelId',
        COMMISIONING_FLAG AS '@IFlag',
        TIMESPAN AS '@Time',
        USERNAME AS '@Username',
        SOURCE AS '@Source'
        FROM #CODES
    FOR XML PATH('Item'),
    ROOT('Co')
)

Temp #CODES table is structured like this:

CREATE TABLE #codes
(
    ID_CODE bigint,
    CODE_LEVEL tinyint,
    CODE nvarchar(20),
    BNUMBER nvarchar(50),
    COMMISIONING_FLAG tinyint,
    IS_TRANSMITTED bit,
    TIMESPAN datetime,
    USERNAME nvarchar(50),
    SOURCE nvarchar(50)
)

What do I have to do add properties to the <Co> root element?