Clone flat.php shipping module, first.
Copy the files:
/includes/modules/shipping/flat.php
/includes/languages/english/modules/shipping/flat.php
to the new filenames for under 1lb to:
/includes/modules/shipping/flatunder.php
/includes/languages/english/modules/shipping/flatunder.php
and to the new filenames for over or equal to 1lb to:
/includes/modules/shipping/flatover.php
/includes/languages/english/modules/shipping/flatover.php
In the flatunder.php files, you need to change all flat to flatunder and all FLAT to FLATUNDER, these are case sensative changes.
In the flatover.php files, you need to then change all flat to flatover and all FLAT to FLATOVER, again, these are case sensative changes.
Next, you need to manage these files so that they work based on the current shipping weight and so that the modules can work in the admin as well for configuring them.
To manage the weight in flatunder.php change the code from:
PHP Code:
// disable only when entire cart is free shipping
if (zen_get_shipping_enabled($this->code)) {
$this->enabled = ((MODULE_SHIPPING_FLATUNDER_STATUS == 'True') ? true : false);
}
to include the code beneath it:
PHP Code:
// disable only when entire cart is free shipping
if (zen_get_shipping_enabled($this->code)) {
$this->enabled = ((MODULE_SHIPPING_FLATUNDER_STATUS == 'True') ? true : false);
}
// hide if greater than or equal to 1lb
if (IS_ADMIN_FLAG == false && $_SESSION['cart']->weight >= 1) {
$this->enabled = false;
}
You can then do something similar to manage the flatover.php for < 1 lb.