SoapUI 3.5 can apparently not be used to test encryption with JBossWS 4.2.3/3.1.1.
JBoss WS clients generate a wsu:ID attribute in the <env:Body> element, which SoapUI omits. This is the cause of your fault.
<env:Body xmlns:wsu='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd'
wsu:Id='element-1-1272320911598-1522000'>
<xenc:EncryptedData Id='encrypted-2-1272320911598-11779585' Type='http://www.w3.org/2001/04/xmlenc#Content'
xmlns:xenc='http://www.w3.org/2001/04/xmlenc#'>
SoapUI:
<soapenv:Body>
<xenc:EncryptedData Id="EncDataId-5" Type="http://www.w3.org/2001/04/xmlenc#Content">
JBoss also generates wsu:ID attributes in the <wsse:SecurityTokenReference> element, which again, SoapUI omits.
And as for testing WS-security, you might think about breaking up your operations and testing in stages: first test encryption using a single keystore, then test encryption requiring signatures, then multiple keystores, etc.