Realex Global Iris payment plugin instead of HSBC

How do I add a payment plugin?
I am building a new website using Joomla 3.0. on my old site I have been using HSBC Secure Pay but they have changed to Realex Global Iris and there is no plugin for it.
What should I do?

There is a RealEx payment plugin for HikaShop developed by willows consulting:
www.willows-consulting.com/Partners/Realex_Payments.html
So I encourage you to first contact them.

Otherwise, if you want to develop it yourself, we have a developer documentation available here:
www.hikashop.com/en/support/documentatio...r-documentation.html

Thank you Nicholas, I will contact them.
Many thanks.
Phil