Can't update table in VS2005 using MySQL

Hello everybody.
I use VS2005 and I was trying to make a little program able to connect
to a MySQL 5.0.18 database through MyODBC 3.51.12. I can connect to the
database and I can load a table in the Datagridview control, but I can't
update the table: the wizard didn't generate the Update method. Even if
I configure again the tableAdapter, the wizard generates only:
SELECT statement
table mappings
Fill method
Get method
The table is a very simple table: it has 3 columns and the first is a
primary key.

If I create an identical table using Access database and make a program
that connects through ODBC, I don't have the problem: the wizard
generates also the UPDATE, INSERT and DELETE statements.

Where is the difference? What is the problem?
Maybe MyODBC doesn't support updating a table? (It can't be true!)

Thankyou so much for the help


Roberto