Authors CurseForge

Just been looking at doing this myself. From looking at the TreeGroup code, I have managed to get this to work:

local treeStructure = { ... as your post ... }
-- Create tree and set status table.
WidgetTree = AceGUI:Create( "TreeGroup" )
WidgetTree:SetTree( treeStructure )
TreeGroupStatus = { groups = {} }
WidgetTree:SetStatusTable( TreeGroupStatus )
--Tell tree that parent 2 should expand.
TreeGroupStatus.groups[2] = true
-- Refresh tree here.

In your case, this should make "Enchants" expand.

There is a library made for scrolling tables, you can find it at:

http://www.wowace.com/addons/lib-st/

I don't know if it will work with AceGUI-3.0 or not.