[xmlsec] Including the X509 ?

[Aleksey Sanin]

It's simple :) :
    1) put <X509Data/> in the <KeyInfo/> to specify you desire to write 
X509 cert
    in the output
    2) Associate the certificate(s) with the key:
        man xmlsec1
        ....
           --privkey[:<name>] <file>[,<cafile>[,<cafile>[...]]]
 
              load private key from PEM file and certificates that 
verify this
              key
        ....

You might want to look at the tests in the xmlsec test suite. Just 
serach for x509 in
tests/testDSig.sh script.

Aleksey