[xmlsec] Get Buffer to Hash and Sign

[Antonio Ruiz Martínez]

Hello!

    I've been finding in the API but I don't know some functions that I
would like to use.

I'll explain you that I want to do.

The steps will be the following:

- Read a xml document with: xmlParseFile
- Create the template signature with: xmlSecTmplSignatureCreate
- Add Signature element: xmlAddChild
- Add Reference and enveloped transform: xmlSecTmplSignatureAddReference
and xmlSecTmplReferenceAddTransform

Then I would like to do the following:
- Get in a buffer the data after the thansformation in order to do the
hash (one buffer for each reference)
- I'll do the hash and the signing on my own
- then I would like to insert the signature information and the keyinfo
in the document

Is it possible to do something similar to this? I can't manage to find
the correct functions, it may be because I'm new with this library.
Can you help me, please?

Regards,
Antonio.