My magento e-shop uses a third party extension that adds an extra fee if cash on delivery is selected as payment method. This extension works without problems. I've purchased another extension that uses Ajax to reduce the checkout steps from 6 to 1. This extension is working fine with default magento but It can't "cooperate" with the payment module in order to add the extra fee at the Grand Total. Please see pictures attached (sorry for the language, the shop is in Greek). And there is also a small problem with a pop up window for rules and conditions that pops up without a reason when you visit checkout page.
What I need is the one step checkout to add the extra fee at "Order Review" exactly as the default checkout and the pop up window to be fixed. The only files that I want to be updated are the files of the "one step Checkout" extension. I can provide an online test e-shop where you can work directly with both extensions installed and a separate zip file of the "one step Checkout" extension. In order for the project to be completed you must send me the updated files so I can upload it to my shop and test them.