Building xml in oracle without unnecessary tags

I wanted to build XML in oracle using sql, I found a way building it using sql functions after a little research, I am completely unaware of any XML. My query is

SELECT XMLELEMENT("orderwave",
             XMLAGG(XMLELEMENT("order_header",
                         -- XMLATTRIBUTES(t2.l_name AS "order_number"),
                          XMLFOREST(
                          nvl(t2.l_name,' ') as "order_number",
                        (
                         SELECT XMLAGG(XMLELEMENT("order_line",
                                       XMLFOREST( nvl(t1.l_name,' ') AS "label_type", 
                                                  nvl(t1.l_num,0) AS "lpn",
                                                  nvl(t1.l_num,0) AS "sku"
                                                )
                                                  )
                                      )  
                          FROM test_table t1
                          WHERE UPPER(t1.record_type)='D'             
                        ) AS sap
                                  )
                                  )
                       )
                       ) AS HEADER
                       FROM test_table t2 
                       WHERE UPPER(t2.record_type) ='H';  

My problem is for using xmlforest, I had to use alias name 'sap' in my query to work and to get xml output. If i am using that, I am getting an unwanted tag 'SAP' around my data which I have to later cut it, which is unacceptable. Is there a way I can get rid of this extra 'SAP' tag without having to cut. The output data is

<orderwave>
   <order_header>
      <order_number>order1</order_number>
      <SAP>
         <order_line>
            <label_type>test1</label_type>
            <lpn>1</lpn>
            <sku>1</sku>
         </order_line>
         <order_line>
            <label_type>test2</label_type>
            <lpn>2</lpn>
            <sku>2</sku>
         </order_line>
         <order_line>
            <label_type />
            <lpn>0</lpn>
            <sku>0</sku>
         </order_line>
      </SAP>
   </order_header>
   <order_header>
      <order_number>order2</order_number>
      <SAP>
         <order_line>
            <label_type>test1</label_type>
            <lpn>1</lpn>
            <sku>1</sku>
         </order_line>
         <order_line>
            <label_type>test2</label_type>
            <lpn>2</lpn>
            <sku>2</sku>
         </order_line>
         <order_line>
            <label_type />
            <lpn>0</lpn>
            <sku>0</sku>
         </order_line>
      </SAP>
   </order_header>
</orderwave>

Any help is really appreciated and thanks in advance.