how do we know that a save operation was successful or not

I am new to csla framework. In my aspx.cs page i am calling say category.save. This goes to the DataPortal_Insert and saves the record and the procedure returns a value which says whether the insert was successful or not. This value is not returned back to the aspx.cs page. So how could i return this value to the front so that i could check its value and say whether the save was succesful or not?

Thanks

Simi