Firefox won't recognize exterior dtd entity references...

[webmasterbeta]

Is this a new W3 xml specification change, or a firefox limitation?

Here's my code to exemplify my q:


xml:
---------------------------------------------------------------------
<?xml version="1.0"?>
<!DOCTYPE ambulances SYSTEM "C:\Documents and Settings\449142\My Documents\Classwork\ambulence.dtd">
<ambulances>
<ambulance>
&driver;
&pcr;
</ambulance>
<ambulance>
<driver>
<firstName>Huey</firstName>
<lastName>Philban</lastName>
<licenseNumber>928373-39</licenseNumber>
</driver>
<pcr>
<pcrNumber>456</pcrNumber>
<patientName>Suzy Que</patientName>
<callTime>21:34:00</callTime>
</pcr>
</ambulance>
<ambulance>
<driver>
<firstName>James</firstName>
<lastName>Kerry</lastName>
<licenseNumber>455476554</licenseNumber>
</driver>
<driver>
<firstName>Stephen</firstName>
<lastName>Corruthers</lastName>
<licenseNumber>103834445</licenseNumber>
</driver>
<pcr>
<pcrNumber>789</pcrNumber>
<patientName>Yeves Primeau</patientName>
<callTime>05:11:00</callTime>
</pcr>
</ambulance>
</ambulances>


dtd:
---------------------------------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT ambulances (ambulance+)>
<!ELEMENT ambulance (driver+,pcr)>
<!ELEMENT driver (firstName,lastName,licenseNumber)>
<!ELEMENT firstName (#PCDATA)>
<!ELEMENT lastName (#PCDATA)>
<!ELEMENT licenseNumber (#PCDATA)>
<!ELEMENT pcr (pcrNumber,patientName,callTime)>
<!ELEMENT pcrNumber (#PCDATA)>
<!ELEMENT patientName (#PCDATA)>
<!ELEMENT callTime (#PCDATA)>
<!ENTITY driver SYSTEM "driver.xml">
<!ENTITY pcr SYSTEM "pcr.xml">


entity ref:
-----------------------
driver.xml:
-------------------------------------------------------------
<driver>
<firstName>Jerry</firstName>
<lastName>Jones</lastName>
<licenseNumber>230988234</licenseNumber>
</driver>

pcr.xml:
------------------------------------------------------------
<pcr>
<pcrNumber>123</pcrNumber>
<patientName>Howard Forbes</patientName>
<callTime>21:34:00</callTime>
</pcr>