Add shipping method option

Hi,

I have created a payment method which has some shipping methods. I want to add a single option in this shipping method select list. How I can do it, I don't want to changed the core files of the hikashop but can create a new file which may extends some other files and create a new option to be displayed in this shipping method list selection. I am really thankful for your any suggestion/help.

Thank you nicolas for your reply, I have created both payment and shipping plugins and I have also a custom view file which is in checkout folder. I want to find the shipping rates using code and I don't want to show my payment and shipping plugin details in the cart templates. I just need to get the shipping rates through code. I am not getting understand which file/function I need to call against what input variables to get the shipping rates, although I have cart detail in my custom view file. I have also posted a new thread for this but could not get the response.
www.hikashop.com/en/forum/2-general-talk...-shipping-price.html
My work has been completed only getting shipping rates are left.
Thanks again for your reply