OK... I've managed to let the reader surf the web AND browse books from Linreb's bookshelf!!
I've installed Privoxy which runs on port 8118. So I configured the reader to use proxy listening in 127.0.0.1:8118.
In Privoxy's main configuration file I've added ONE line "forward .ebooksystem.net 127.0.0.1:9090" (without quotes).
So, to surf the web, you only need to put an index.html file on Linrebs store directory pointing somewhere on the internet. In the reader you go to BOOKSTORE and click the icon and Linred should respond with that index page you created, after that, click on the link and VOILA!!
Is it clear?