Magento 1- Keep Handling fee on free shipping price rule

Question

We currently offer Standard Shipping, which can bee set to "for free" on certain products by shopping cart price rule.
Now we want to offer an additional "priority shipping" with an extra fee.
Of course if the customer selects this we want to keep this fee, even when the shipping itself is free. With the default shopping cart price rules this doesn't seem to be possible.

How can we do this?

I was able to get the totals in the order correct by avoiding the "free shipping" option in the shopping cart price rules and working with discounts instead but then the shipping cost selection in the checkout isn't anymore which is bad for usability, it needs to look like this:

Standard Delivery - 0,00
Priority Shipping - 5,00

But it looks like this:

Standard Delivery - 15,00
Priority Shipping - 20,00

and then before Submitting the Order in the totals:

Some totals             123,45
Discount               -15,00
Shipping & Handling     20,00

I currently have no idea on how to solve this.
Easiest way would be if there's an extension that could do this.
But every kind of input is appreciated.

Answer 1

I think you can use this free module https://github.com/PHOENIX-MEDIA/Magento-CashOnDelivery

This helps you to create a new payment method with handling charge. You can just change the name as you wish in the backend and it calculates a separate handling fee when a user selects this payment method.