netscap / IE external entities

[Shawn Modersohn]

Can someone give me the lowdown on the way these two browsers deal with
the following

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/css" href="datadump.css"?>
<!DOCTYPE datadump [
<!ENTITY sig SYSTEM "signature.xml">
<!ENTITY txt "this is an entity">
<!ELEMENT datadump (name)>
<!ELEMENT name (first,last)>
<!ELEMENT first (#PCDATA)>
<!ELEMENT last (signature)>
<!ELEMENT signature (#PCDATA)>
]>
<datadump>
<name>
<first>&txt;</first>
<last>&sig;</last>
</name>
</datadump>

In IE, without a style sheet, the document tree shows the signature
element within the last element. With a stylesheet, IE only displays
the signature content. Just by having an external entity, IE seems to
only display that content and nothing else.

In Netscape, without a stylesheet the document tree shows last as any
empty element.

In other words, in differing ways, neither is doing as I would expect,
insert the external entity where I want it while being styled according
to my specification.

xmlvalid says the xml is valid so I figure it is a difference in how the
browsers treat external entities.