I imported my journal a long time ago, and my community entries did not come with. I'm pretty sure they won't be coming with for the latest importees, either.

I'm fairly certain that, in order to get those entries over to Dreamwidth without manually re-posting them, you have to import the actual community. Which is an option! If you're one of the community moderators on LJ, you can probably do it yourself even.

Good luck!