Change a cck field according to the title

I was creating another issue for a complicate challenge I have and here I am trying to manipulate around this.
So what I do is create a rule that create new entity>>new node for each line_item purchase.
The title will be the line_item_label.
Using pathauto I get my results url -
- ../big-1
- ../big-2
-../small-1
- ../small-2
- etc.
But since it's using the page title I might be in trouble.
So, I created a cck field in that node type, text field that I need him to fill up with the title of the node.
Can't find the way to do so...