I made these corrections to my full program and DTD and I still have a problem. If I have a 'type' element defined, then the 'type' attribute is still getting converted to a tag inside the 'phone' element.

use XML::Smart;

my $xml = XML::Smart->new;
$xml->{customer}{phone} = "555-1234";
$xml->{customer}{phone}{type} = "home";

$xml->apply_dtd(<<EOF);
<?xml version="1.0" ?>
<!DOCTYPE customer [
<!ELEMENT customer (type?,phone+)>
<!ELEMENT phone (#PCDATA)>
<!ATTLIST phone type CDATA #REQUIRED>
<!ELEMENT type (#PCDATA)>
]>
EOF

print $xml->data;
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This produces:

<customer>
  <phone>
    <type>home</type>555-1234</phone>
</customer>
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