How to add a prefix to an PBDOM element

I have an recursive function to read XML documents using PBDOM

Now I want to add some new elements with or without an prefix depending on the original xml document.

everything looks like ok but I miss the xml-prefix in the new added elemens in the new document.

...

ls_type = pbdom_obj_array[ll_loop].getname()

...       

CHOOSE CASE ls_type

  CASE "nichtangeboten"

      SELECT "lv_lohn", "lv_sonstiges", "lv_betrag"

      INTO :lv_lohn, :lv_sonstiges, :lv_betrag

      FROM "lvpositionen" WHERE "lv_nummer" = :onlv_daten.lv_nummer and "lv_baustellenr" = :onlv_daten.projektnr;

      if NOT isNull(lv_betrag) and lv_betrag <> 0 then   

          pbdom_obj.RemoveContent(pbdom_obj_array[ll_loop])

          //ns_prefix = pbdom_obj.GetQualifiedName()

          PBDOM_ELEMENT pbdom_elem0, pbdom_elem1, pbdom_elem2, pbdom_elem3, pbdom_elem4

          pbdom_elem0 = Create PBDOM_ELEMENT

          ns_prefix = pbdom_obj.GetNamespacePrefix ()

  //ns_prefix examle: on                

          ns_uri = pbdom_obj.GetNamespaceUri()

          pbdom_elem1 = Create PBDOM_ELEMENT

          pbdom_elem2 = Create PBDOM_ELEMENT

          pbdom_elem3 = Create PBDOM_ELEMENT

          pbdom_elem4 = Create PBDOM_ELEMENT                       

          if isNUll(lv_lohn) then lv_lohn = 0.00

          if isNUll(lv_sonstiges) then lv_sonstiges = 0.00

          if isNUll(lv_betrag) then lv_betrag = 0.00

          pbdom_elem0.SetName("preis")       

  //what I want is <on:preis>10.00</on:preis>

  //but I get <preis>10.00</preis>

  //wrong, adds an attribute not the prefix :-(                               

  /*    if ns_prefix > ' ' and ns_uri > ' ' then 

              pbdom_elem0.AddNamespaceDeclaration(ns_prefix, ns_uri)

          end if       

  */   

          pbdom_elem1.SetName("preisanteil1")

          pbdom_elem1.AddContent(f_changecharacters(string(lv_lohn, "0.00"), ',', '.'))                                           

          pbdom_elem0.AddContent (pbdom_elem1)

          pbdom_elem2.SetName("preisanteil2")

          pbdom_elem2.AddContent(f_changecharacters(string(lv_sonstiges, "0.00"), ',', '.'))

          pbdom_elem0.AddContent (pbdom_elem2)

          pbdom_elem3.SetName("gesamt")

          pbdom_elem3.AddContent(f_changecharacters(string(lv_betrag, "0.00"), ',', '.'))

          pbdom_elem0.AddContent (pbdom_elem3)

          pbdom_obj.AddContent (pbdom_elem0)

          pbdom_elem4.SetName("pospreis")

          pbdom_elem4.AddContent(f_changecharacters(string(lv_betrag, "0.00"), ',', '.'))

          pbdom_obj.AddContent (pbdom_elem4)

          destroy pbdom_elem0

          destroy pbdom_elem1

          destroy pbdom_elem2                       

          destroy pbdom_elem3

          destroy pbdom_elem4           

      end if

  CASE "preis"

  ...