QUESTION ABOUT PKCS#7 AND XMLDSIG

  Please a have a question :

In the [Extensions and Revisions to PKCS #7 - Burton S. Kaliski Jr., 
Ph.D. and Kevin W. Kingdon 1 - An RSA Laboratories Technical Note - May 
13, 1997 - http://security.ece.orst.edu/koc/ece575/rsalabs/bulletn6.pdf 
] thay said that :

{ PKCS#7 has become the basis of S/MIME, SET, ....also PKCS#7 become a 
basis for message security in systems as diverse as the W3C Digital 
Signature Initiative, ...}.

My question is : What they mean about basis  .

Does xmlDSIG use pkcs#7? or xmlDSIG uses the same method (or logic) as 
that of pkcs#7?
What is the relation between pkcs#7 and XMLDSIG?

Thanks

jacques