ok i finished the plugin and its working but it needs a lot of development wich i´m not able to do, thanks to a friend we managed to achieve it.
1.- Its created based on hikashop servired´s pluging and as i dont know how to modify a lot of code it still has the same programation so in the confirmation message it show servired.
2.- In ceca you have to activate online_comunication and there insert the confirmation webpage http://mywebsite/index.php?option=com_hikashop&ctrl=checkout&task=notify¬if_payment=servired, wich it should be better create a new file .php to call to the function but i dont know how to do it.
3.- In hikashop servired_end i changed the address url ok because when ceca returns to my page it only displays a white window with my menu and nothing more and i would like to return to my main page with the message order finished or similar, as i dont know how to do it, i´m going to create a custom landing page that should be changed in firm calculation and in input field url ok
4.- the main changes are in the file servired.php and you can see them as new adds or something similar...
5.- by default we generate a file to see if what we recieve from ceca is ok and for further testing called vblePOST.txt in the root of the server.
6.- To create the plugin i just overwrite servired one.
7.- I´m sure you can do it better than me, but now its functional.
hope you continue with developing and add the pluging well done in next release or asap
Thank you
David Pintado