International Shipping Costs?

I would like to add the option for International Shipping to a cart, however I do not know what the various charges might be, so I want to contact the buyer after purchase with the total amounts include shipping. How can I set that up in the cart?

Anyone know how to do this?

Is there a reason why you cannot use a realtime shipping method to accurately calculate your costs while the order is being placed (& paid for)?

Would sure make your / someones job far easier vs. having to come back & manually tweak the shipping costs for each order & collect the payment differences.

No matter how you go about this, it will be messy & create far more work in processing each order you take.