They have augmented the 'Create Tin' tool to do all of the processing like the old toolbar button did. The old 'Create TIN' did not include data, but the new one does. I agree the help needs to be updated for version 10 and I have indicated as much on the feedback for the page. If you see something like that I encourage using that feedback button. It is a little button with a pencil on it.
As far as the TIN Chris mentioned, it appears that you are using your boundary as a Hard Clip rather than Soft clip. I would create the TIN again and this time, specify a soft clip and remove the height for that feature.
I'm wondering why ESRI couldn't includes all the commands in the ArcToolbox. It's quite crucial for the user to access all the commands from one place!
second, some times, the same command has two different names! one name in the Arctoolbox and other name in the toolbar minue!
All of the commands have always been in ArcToolbox. The toolbar was what was limited in functionality. It only contained a subset of tools that 3D Analyst offered.
This is one of the very reasons the toolbars from Spatial Analyst and 3D Analyst had their tools removed. Different names, different parameters, different UI's, different environments/options, all led to confusion for many users. The full power of these extensions (analytically anyway) has always been and remains in ArcToolbox.
Regards,
Eric