src/Tasks/ShopMigrationTask.php
public function migrateShippingValues($order)
    {
        //TODO: see if this actually works..it probably needs to be writeen to a SQL query
        if ($order->hasShippingCost && abs($order->Shipping)) {
            $modifier1 = Base::create();
            $modifier1->Amount = $order->Shipping < 0 ? abs($order->Shipping) : $order->Shipping;
            $modifier1->Type = 'Chargable';
            $modifier1->OrderID = $order->ID;
            $modifier1->ShippingChargeType = 'Default';
            $modifier1->write();
            $order->hasShippingCost = null;
            $order->Shipping = null;
        }
        if ($order->AddedTax) {
            $modifier2 = \SilverShop\Model\Modifiers\Tax\Base::create();
            $modifier2->Amount = $order->AddedTax < 0 ? abs($order->AddedTax) : $order->AddedTax;
            $modifier2->Type = 'Chargable';
            $modifier2->OrderID = $order->ID;
            //$modifier2->Name = 'Undefined After Ecommerce Upgrade';
            $modifier2->TaxType = 'Exclusive';
            $modifier2->write();
            $order->AddedTax = null;
        }
    }
public function migrateShippingValues($order)
    {
        //TODO: see if this actually works..it probably needs to be writeen to a SQL query
        if ($order->hasShippingCost && abs($order->Shipping)) {
            $modifier1 = Base::create();
            $modifier1->Amount = $order->Shipping < 0 ? abs($order->Shipping) : $order->Shipping;
            $modifier1->Type = 'Chargable';
            $modifier1->OrderID = $order->ID;
            $modifier1->ShippingChargeType = 'Default';
            $modifier1->write();
            $order->hasShippingCost = null;
            $order->Shipping = null;
        }
        if ($order->AddedTax) {
            $modifier2 = \SilverShop\Model\Modifiers\Tax\Base::create();
            $modifier2->Amount = $order->AddedTax < 0 ? abs($order->AddedTax) : $order->AddedTax;
            $modifier2->Type = 'Chargable';
            $modifier2->OrderID = $order->ID;
            //$modifier2->Name = 'Undefined After Ecommerce Upgrade';
            $modifier2->TaxType = 'Exclusive';
            $modifier2->write();
            $order->AddedTax = null;
        }
    }
Convert shipping and tax columns into modifiers

Applies to pre 0.6 sites