libvirt users - May 2013 - Virsh with CPU features on XML file not working!

Hello,

Does anyone have masked their CPU flags with Libvirt?? It's because
I have done so with Libvirt and Virsh compare / baseline. But when
I boot the DomU I see the same flags as if I hadn't declare de <cpu>
tag containing the features just as is described in:
http://libvirt.org/formatdomain.html#elementsCPU

I posted here my XML file definition:  http://pastebin.com/ze5wvSZt

I would be really grateful if someone shared your domain XML definition
with me or tell me the syntax. I've been struggling for hours, just
you know, following the documentation available but there is no
functionality for me yet.

Thank you a lot!

Antonio Colín.