I am using a demo version of Wordfast Pro.
Glossaries work just the same in demo mode and in licensed mode.
I imported a local glossary from my desktop. I added few terms through Wordfast Pro but could not see them added to the original local glossary.
When you say you could not "see" the terms added, do you mean that:
1) said terms are not surrounded by a frame (and displayed in red/green) in the source segment
2) you cannot see them if you browse through the glossary via Terminology > Edit > [name of glossary]
What language did you use as source? Can you give a couple of sample source terms you tried to add to your glossary?