Then you may be able to define a couple of hooks for freezing and thawing XML::LibXML::Element objects

# these are completely untested!

sub XML::LibXML::Elemment::STORABLE_freeze {
   my $self = shift;
   $self->toString;
}

sub XML::LibXML::Elemment::STORABLE_thaw {
   my $class = shift;
   my (undef, $str) = @_;
   XML::LibXML->parse_xml(string => $str)->documentElement;
}
[download]

See the "Hooks" section in the Storable documentation.

Note that if you serialize two elements from the same document, they will be part of two documents when deserialized.

Thanks very much for your help. After some tweaking it seems to work. I've ended up with this code:

sub XML::LibXML::Element::STORABLE_freeze {
    shift->toString
}

sub XML::LibXML::Element::STORABLE_attach {
    'XML::LibXML'->load_xml(string => pop)->documentElement
}
[download]

Thank you very much! I'll give it a try on Monday and post the result here.