Running the Glossary Hotspot Wizard is a one time shot. It's a single pass through the pages where RoboHelp scans topics for terms and creates the Expanding hotspots containing the definitions. Once complete, you should be able to edit the expanding hotspots freely. Unless RoboHelp 8 has bowled us a wobbly, there shouldn't be anything that would preclude you from editing the expanding hotspots to read as you wish.
It appears that RH looks up glossary terms by name ie: if you look at the html it says <?rh-glo_start ?>Tree<?rh-glo_end ?>. If i change the content from Tree to Trees then the glossary item is no longer clickable in my doc.
Hmmm, it would then seem this is no longer possible in RoboHelp 8. I knew there were some changes to the way the Glossary was handled, but didn't realize they would be quite that dynamic.
If this is for just one or two terms, you might be better off just performing a manual edit to remove the Wizard inserted hotspot and replace it with a simple DHTML expanding hotspot.
Then again, I see where you were also asking about converting to tooltip style presentation. So that may muddy the waters big time if you did that.
Sorry I have nothing better to offer! Rick