When i attach MS Outlook *.msg file as a Outlook Dataset, there are possibility to view this message into TC or should I use export and open outside Teamcenter?
You can set the viewer of that dataset to be the same as for the html dataset.
this will open the msg file in outlook
but it will open it in outlook outside of Teamcenter viewer
On Windows the msg mime type is usually connected to Outlook and you should be able to view your mail by double-clicking the Outlook dataset. As msg has binary format I don't see an easy way to display it e.g. in the viewer.