sub SOAP::SOM::childof {
  my $self = shift;
  local $self->{_current} = $self->{_current};
  $self->match(shift) if @_;
  return wantarray ? map {o_child($_)} @{$self->{_current}}
                   : @{$self->{_current}} ? o_child($self->{_current}->[0]) : undef;
}

print Dumper($som->childof('/Envelope/Body/[1]/[1]'));