Felipe - I have to confess that I haven't done it yet! I know, I know, I ended up procrastinating. I may end up doing it soon, b/c lately I've been having some issues with syncing from Music Monkey to my e280.

According to the Rockbox page, it should work pretty well. Just make sure your hw version is v1.
http://www.rockbox.org/wiki/SansaE200Port