Not familiar with netterm but the website mentions it does have VBA available. With VBA it's often possible to manipulate local files. Spectrum magazine had an artivle in the May/Jun 99 issue about
VB and VBA from terminal programs. Check out
Natec Systems - Articles for just creating new excel check out Tony G's program I mentioned above (don't like links in posts - I've never seen him do a straight link - always has a "remove-this" in there" - but a quick google search will bring it up easily). Tony's a great guy and always willing to help - you should talk to him. You can also check out the Mar/Apr 2002 issue of Spectrum for creating the older format Excel spreadsheets.
Back to the terminal program, you can also check out Accuterm... one of the programs I was thinking of in my previous post. With it you can manipulate the local user experience from the host (ie host push of files, execute & interact with other programs, etc.). Accusoft has a decent forum with a pretty active community that addresses these types of questions for Accuterm users. The one thing I wouldn't recommend with Accuterm (and others would disagree) is GUI apps - the speed is painful IMO.