[xmlsec] namespace prefixes on Signature

[Aleksey Sanin]

 > Would it be possible to change xmlSecTmplSignatureCreate() to
 > allow the caller to specify a namespace prefix?

Sure, nothing is impossible, it is only software :) I don't like
the idea of changing the signature for existing function. But one
of the options would be to create a new function that would set
xmldsig, xmlenc, etc. prefixes globally for the whole application.

If you create a patch then I'll be happy to apply it :)

Aleksey