I'm about to install Zimbra on a VM for testing/playing, and would like to import some mail data from a Lotus install. Unfortunately it is an R5 setup and the migation wizard seems to support only R6 and above.

Can I assume that (as IMAPSync is recommended for migrating from other configurations) that the mail stores in Zimbra are hosted by a standard IMAP daemon so I can use a beafed up (so it supports attachments) variant of http://www.perlmonks.org/?node_id=136382 to extract the data from Notes/Domino and use the IMAP+MIME manipulation components I have licenses for to push that data into the Zimbra mail store?

Better still: is there already an easier way to migrate mail data from Notes/Domino R5 into Zimbra? The loss of calendar data would not be a large problem (old data is not absolutely needed as meeting confirmations and such for past events exist in the mail documents and the number of future events will be small enough to re-enter), but if that too could be transferred over it would be useful.

FYI: I am currently looking at the options a small business has for upgrading/replacing and ageing Lotus Domino setup with something that works and isn't just plain irritating. As upgrading Notes will involve retraining (the previous Notes admin has left the company) other options are being considered including Zimbra (the open source edition initially but as the company's needs grow the Network Edition would likely be needed later).