OpenSAML user discussion

Hello all!
I'm trying to verify a response and I getting this excepction,
I am using the verifiying examples provided in xml-security-1_3_0 library, 
Any idea of how can I to solve it?? 



org.apache.xml.security.signature.ReferenceNotInitializedException: Cannot 
resolve element with ID _2d84cf731412b40710be67f61ca525a1
Original Exception was 
org.apache.xml.security.utils.resolver.ResourceResolverException: Cannot 
resolve element with ID _2d84cf731412b40710be67f61ca525a1
        at 
org.apache.xml.security.signature.Reference.getContentsBeforeTransformation(Unknown
 Source)
        at 
org.apache.xml.security.signature.Reference.dereferenceURIandPerformTransforms(Unknown
 Source)
        at 
org.apache.xml.security.signature.Reference.calculateDigest(Unknown Source)
        at org.apache.xml.security.signature.Reference.verify(Unknown Source)
        at 
org.apache.xml.security.signature.Manifest.verifyReferences(Unknown Source)
        at org.apache.xml.security.signature.SignedInfo.verify(Unknown Source)
        at 
org.apache.xml.security.signature.XMLSignature.checkSignatureValue(Unknown 
Source)
        at 
org.apache.xml.security.signature.XMLSignature.checkSignatureValue(Unknown 
Source)



Thanks,