add new plugin to hikashop extension

hello every body,
I'm newbie in joomla so pardon me if i state my question vaguely,
I need to use another bank cart that is not listed in the current avaiable cart listed in hikashop plugins
i need to add a new task in hikashop plugin but it seems to there are some constrains on that because i redirect to another path when i use sth like this mysite.com/index.php?option=com_hikashop?task=end_ircart&order_id=230 what can i do that to pass these constraints?




i try to hack end task in checkout controller but it doesn't work.
thanks alot in advance