Yes, there's a way to transfer ALL of your old entries and ALL of the comments on them, with their dates. The queue is backed up right now, so it takes a couple of days running in the background, but it's fairly straightforward: you give DW your LJ password so it can log in as you, start the transfer job, log out, and you'll get periodic inbox messages about the job's progress while continuing to use LJ and/or DW as usual.