Try adding their file extensions to the Active X plugin (via Settings -> Preferences -> Plugins -> Viewers).
Try putting them under Internet Explorer first and if that doesn't work remove them from that section and try Generic ActiveX instead.
This is assuming that you have the products installed and they provide an ActiveX viewer and/or IE plugin for viewing their formats. If not such things may be available as separate downloads and, if they exist, should work in Opus via the ActiveX plugin.