This is a modified version of backend.php, that offers one way of gathering rss feeds from every module that you'd like and displaying them.
All you have to do is replace the backend.php file with the one in the download package.
Add a file in the modules folder /incude/rss.inc.php
The function name must be modulename_rss()
There is an example of the calendar module and smartsection in the package as well.
It actually works like the search functionality works in xoops but you dont have to change or declare anything on xoops_version.php of each file.
I did that cause i didnt want to change any module core files for it to work.
I have also updated the system_rss.html template (you dont need to (for it to work) but it is included in case you prefer the new one)
If anyone else implements this please share the files for other modules too and send them to me so i can include them in the package.
Download from here