XMLSignatureException: The requested algorithm ... does not exist

["Stephen Chell (DSL AK)" <St...@datacom.co.nz>]

I'm getting the following exception in Websphere Application Server 5.1
(which uses JRE 1.4.1) when I attempt to instantiate an XMLSignature object
from a fragment of XML.  
 
org.apache.xml.security.signature.XMLSignatureException: The requested
algorithm http://www.w3.org/2000/09/xmldsig#dsa-sha1
<http://www.w3.org/2000/09/xmldsig#dsa-sha1>  does not exist. Original
Message was: null
Original Exception was java.lang.NullPointerException
 at
org.apache.xml.security.algorithms.SignatureAlgorithm.<init>(SignatureAlgori
thm.java:217)
 at org.apache.xml.security.signature.SignedInfo.<init>(SignedInfo.java:213)
 at
org.apache.xml.security.signature.XMLSignature.<init>(XMLSignature.java:281)
 at
nz.govt.ssc.eai.common.message.EAIMessage.verifyMessageSignature(EAIMessage.
java:434)
 ... 24 more
 
 
It works fine in Tomcat 4.1.29 using JDK 1.4.2_04, but in Websphere I get
the above exception.  My understanding was that the crypto algorithms come
built in to JDK 1.4 and above.  Is that correct?  If so shouldn't it work
with WebSphere, which uses 1.4.1?
 
Thanks in advance ...
Steve