Boy! replies are slow on this site. I resolved my problem. The cell I needed to alter was really a div inside of a cell. I couldn't see the div until I double-clicked on the cell. So to resolve my problem:
1- I found the cell
2- I moved to cell and double-clicked with an action
3- I discover and find the div
4- I click on the div
5- I clear the div
6- I send string to the div
7- i send the Enter key to div to store the value in server (this is needed in my application)
8- released action
PS: Strings and Integers were accepted since conversion is done at the server.