I have to change some legacy code that was generated with CodeSmith using NetTiers templates. I need to add some new columns and I don't have the original template neither a CodeSmith licence. Is there any way to add them without use CodeSmith?
Yes, you definitely can. Nettiers is nothing more than automatically generated c# code, there is nothing special about the resulting code, you can modify it to your hearts content.
That said, manual modification of the type you are talking about it going to be a bit time intensive. If this is not a one off, I would highly suggest getting Code Smith and trying to regenerate.
In order to manually accomplish your goal, you will need to modify the entity class itself, also all get and save methods that you want to use the new columns, and finally the procedure xml and the stored procedures themselves. It's the same process as if the entire DAL was manually written in c#.
Another option you have is to add the new columns to the end of the tables, then use some other DAL to manage the data in them. As long as the new columns are only added to the end of the table nettiers will completely ignore them.
If your nettiers is using stored procedures to access the data, then as long as the column positions inside the stored procedures don't change the column positions themselves wouldn't matter either. I haven't tested to see if that holds true for parameterized queries built by nettiers though.