Hello Mariano,
Sorry for the late response, but after reading your replies I understand
more your requirement, and I'm sad to inform you that we don't currently
have the ability to manipulate the elements in the "head" of the HTML
doc from a portlet.

BUT, there is an
optional portion of the JSR-286
Portlet
Specification 2.0 Proposal which DOES define such a mechanism, which
would enable us to make the Journal have the ability to do what you
describe, and I'm on a research mission to see if we can get this in
sometime soon.
I'll quote the portion of the proposal here for reference:
[quote=JSR-286 - Portlet Specification 2.0 (Proposed)]
PLT.12.5.4
Setting Markup Head ElementsA portlet can set markup head elements at the response via the
addProperty method with
MimeResponse.MARKUP_HEAD_ELEMENT (value:
"javax.portlet.markup.head.element")
as property name and an org.w3c.dom.Element value.
This property is intended to be a hint to the portal application that
the provided DOM
element should be added to the markup head section of the response to
the client.
Support for this property is optional and the portlet can verify if the
calling portal
supports this property via the MARKUP_HEAD_ELEMENT_SUPPORT
property on the
PortalContext.
Even if the calling portal supports this property, delivery of the DOM
element to the
client cannot be guaranteed, e.g. due to possible security rules of the
portal application or
elements that conflict with the response of other portlets.
For render calls, portlets should set head properties in the render
headers part of the
render lifecycle phase or simply override the
GenericPortlet.doHeaders method (see
PLT.11.1.4.3) in order to run with maximum performance on all portal
implementations.
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