Adding prefixes to XML nodes

i have some classes

class a{ public b _b = new b()...}
class b{...}
class c{...}
class z{...}
class q{...}

they are building a complex class which contains all this classes

class X{
  public a _a = new a();
  ...
}

when i seralized this X to a XML it has been serialized like below

<a><b><c></c></b><z><q></q></z></a>

But i want to add some prefixes to them at the class level like below

<a><sh:b><sh:c><mh:d><mh:/d><sh:/c><sh:/b><z ef:>< ef: q><ef: /q><ef: /z></a>

i have tryed to add from attribute by XmlRoot attribute but it just added first node

is there any manner.. thnks...

Hamit YILDIRIM