store.sync() doesnt add action=create or action=delete.....parameters

Hy,

I am using a GridPanel and when I delete or update or create a Model in the grid , when I call sync in the store it makes always a post request with the updated or deleted or created but I dont see any parameters which distinguish the ones which have to be updated or deleted .....

1. am I missing something?

2. I am using an Ajax proxy

3 Shoud I see any parameter like action=create or something?

Thanks

store.sync() doesnt add action=create or action=delete.....parameters