The map type is a shortcode parameter (‘maptypeid’), not part of the query, so this one should work:
[mashup query="post_type=port" maptypeid="roadmap"]
However, it sounds like ‘roadmap’ has been removed from the ‘map types’ section on the settings screen? If so, the ‘maptypeid’ will be ignored. The setting isn’t a default type – it determines which types are allowed.