Did you subscribe the Nabble archive to the mailing list?
If not, please do this:
http://n3.nabble.com/mailing_list/SubscribeToMailingList.jtp?node=692576Old messages must be imported separately. You should send us an MBOX file so that we can import it. You may contact sourceforge about this, but I am not sure how easy will be to get ahold of this file.