sp:X509token assertion problem

Hi all,
i have a problem with this policy. The problem is that <sp:X509Token>
assertion causes " Undeclared namespace prefix "sp" and the exception i
quoted after the policy. The strange thing is that without this assertion,
i haven't this error; and other assertions that use "sp" doesn't cause any
error. Anyone has some ideas?
Thanks a lot!
Regards,
Filippo Agazzi - University of Parma - Italy


<wsp:Policy
        xmlns:wsu="
http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd
"
        xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy" xmlns:wsa="
http://schemas.xmlsoap.org/ws/2004/08/addressing"
        xmlns:sp="http://schemas.xmlsoap.org/ws/2005/07/securitypolicy">
        <sp:IssuedToken
            sp:includetoken="
http://schemas.xmlsoap.org/ws/2005/07/securitypolicy/IncludeToken/AlwaysToRecipient
">
            <Issuer xmlns="
http://schemas.xmlsoap.org/ws/2005/07/securitypolicy">
                <Address xmlns="http://www.w3.org/2005/08/addressing">
                    http://localhost:8082/STSNegotiation/services/STS
                </Address>
            </Issuer>
            <sp:RequestSecurityTokenTemplate>
                <t:TokenType xmlns:t="
http://schemas.xmlsoap.org/ws/2005/02/trust">
                    urn:it:unipr:TrustNego:AccessToken
                </t:TokenType>
            </sp:RequestSecurityTokenTemplate>
        </sp:IssuedToken>
        <sp:X509Token sp:IncludeToken="
http://schemas.xmlsoap.org/ws/2005/07/securitypolicy/IncludeToken/AlwaysToRecipient"
xmlns:sp="http://schemas.xmlsoap.org/ws/2005/07/securitypolicy"/>
    </wsp:Policy>


Exception:

org.apache.axis2.dataretrieval.DataRetrievalException:
com.ctc.wstx.exc.WstxParsingException: Undeclared namespace prefix "sp" at
[row,col {unknown-source}]: [7,170]
org.apache.axis2.dataretrieval.AxisDataLocatorImpl.getData(AxisDataLocatorImpl.java:85)
org.apache.axis2.description.AxisService.getData(AxisService.java:2964)
org.apache.axis2.description.AxisService.getWSDL(AxisService.java:1645)
org.apache.axis2.description.AxisService.printWSDL(AxisService.java:1413)
org.apache.axis2.transport.http.ListingAgent.handleWSDLRequest(ListingAgent.java:327)
org.apache.axis2.transport.http.ListingAgent.processListService(ListingAgent.java:183)
org.apache.axis2.transport.http.AxisServlet.doGet(AxisServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)