[xmlsec] XML digital signature enveloped

[Aleksey Sanin]

By definition, enveloped transform returns the node set that contains
all the nodes in the document except the <dsig:Signature> subtree.
If you want to sign only a content of a particular node then you probably
need to use XPath transform instead. If you can achieve your goal
with template and xmlsec utility then imgrating to a dynamically
created templates is pretty straigthforward: just call correct functions
in correct order (and you always can dump the dynamically created
template to a file to verify that you are creating exactly what you want).

And there is no difference between missing and empty URI attribute
in the <dsig:Reference> element.

Aleksey