Mandatory field in shipping

I am using LiteCart 1.3.4 and the free add-on "Pickup" as payment/shipping method.

I would like to add a field at the checkout shipping box where the customer has to choose a date when the order should to be picked up.

Is it possible to have mandatory fields/choices in the shipping function?

You can pass some input fields to the return parameter named fields.

The user data can be picked up in the method select() in $_POST or $this->userdata.

LiteCart doesn't do anything with the data, so you need to code what's going to happened with the collected data.

Although the wiki doesn't say much about user data, here is the wiki link for shipping modules:
http://wiki.litecart.net/doku.php?id=how_to_create_a_shipping_module