Wow, thanks Tom!. Downgrading the JSP engine seems to work as I do not get any exception/error now, well no errors anywhere rather than 404 on the browser.
Hence, I need the sources of the packages added from Indigo R2 in order to see what it is going wrong at this time. Unfortunately, I'm unable to find such old sources as they seem as don't migrated to Git and I'm neither able to find the old repository (Subversion?).
Might you please share the the url or the source bundles?
Thanks very much!
Pablo.
PS: As far as I can see currently, the jsp alias has been resolved against the registry and something is happening form inside the JspServlet. Looking into the sources of Luna it it would be failing due an unexpected configuration (the JspServlet thinks it is running on an Tomcat compatible environment which is not true in this case. It is running under a very constrained environment provided by the Atlassian's plugin framework which provides a customized servlet environment not fully compatible with Tomcat: no "WEB-INF" folder exists, for instance...).