Hmmm. If you look at ...
http://www.fjsoft.at/en/news.php ... under the 1.8.2 release IM is mentioned as having been added. But I can't see it under a column heading in 1.8.6 (right click in the contacts top bar where the column headers are). However, each contact has an 'IM Messenger' tab on which you can add an address. As you say though, the Outlook data is not transferred which is odd.
However, note that Android contact apps do not show all numbers from Outlook even if they are recognised by MPE. I created a test contact in Outlook which utilised EVERY number field (**) they show to determine which fields were transferred or not. Not only do a lot of apps only show a small subset of numbers but I also found that if two were the same (which often happens with small companies who share a fax number with their main office number, for instance) then only one was shown.
I only managed to get any help from DW Contacts who changed their code to ensure that a) all contact details in the database were shown and b) they displayed them even if they were the same in the above case.
** - obviously things like 'ISDN' and 'Telex' aren't that useful these days, at least in most of the developed world, but if the fields exist they should be transferred.