Insert information into a specific datagrid cell

I am using a datagrid connected to an SQL server via an ADO connection.

I need to be able to insert a value into a hidden datagrid field via code. How can I do this?

Example:

I am displaying the data in a datagrid. I have set the visibility of the Payrate field to false, for security purposes. Now what I want to happen via code. When the user adds a record to the datagrid they enter the machine number in it's cell. I will use an SQL statment to get the payrate for that particular machine. (I can get this to work). Now for the real problem. How can I set the payrate cell in the added record to the payrate for that machine number.

If this is not clear e-mail me or post any questions you have of me.

If anyone can help with this... I thank YOU.