Date and author information of revision changed when creating new revisions

We use revisions for different revisions of a certain document, which can be changed by several users. However, when user1 creates a story, and user2 creates a new revision of that story, both will be displayed as authored by user2.
In addition, both articles will get the publication time of the newer revision assigned when displaying the story. This is confusing, especially as there can be months (or even years) between revisions.

In addition, as we are moving old content from a static html site to a Drupal-6 base site, including revisions of articles, it always assigns the actual revision time to a revision, not the manually entered publication date. Again, this might not be a problem for new content, but is a problem when moving legacy content (i.e. we have revision1 published in 1998, revision2 in 2005).