Binary Security Token - Encrypt the Signature

Hi.

I've been trying to set this up for some time now, but no search of brute force has yielded any resulsts:

What I need to do is to encrypt the signature that is included in the security header. I've realized that adding the header elements in different order will change wether the body is encrypted before signing or signed before encrypting. However, I am unable to encrypt the signature after signing. This is a requirement for the service we are creating and we wish to test it in SOAP-UI in addition to integration tests.

Is this possible? Am I blind? Can anyone help me?

thanks.