For interested people, someone from b2evolution gave me a nice idea : to generate an export from Dotclear to Movable Type format.
As b2 and WP handles import from MT, this converter will be easy to be used from both WP and b2 community 😉
More info at : http://forums.b2evolution.net/viewtopic.php?p=22878#22878
I understand the point but I’m not familar with WP for the moment. So what do you do in WP to import the RSS feed ?