I need to add a custom Ajax search form in Magento admin in "Customer Information" => "Orders". Form search by id, sku, and product names.
![screenshot](http://i.stack.imgur.com/rZD8v.png)
I do not know where to start.
I know how add sort to grid header, know how make Ajax request, Know how add/remove standart buttons like "search", "reste filter" etc. But don't know how add custom search form near/in filter-actions buttons ![Smiley Sad Smiley Sad](/i/smilies/16x16_smiley-sad.png)