gateway integration with k2store and authorize.net simulator

My website uses the latest version of Joomla (3.x). The template used is built using K2 and K2 Store. There were conflicts with this combination but were resolved by the template creators. In order to process payments on the website there must be a plugin that will send information from the K2 Store to the payment processor which is NMI. We have to use an [login to view URL] simulator because this is the only thing NMI can provide to connect generically. The [login to view URL] simulators, when installed, do not even ask for the complete and proper data to make a connection to NMI. For instance it does not ask for any links to the API or MD5 Hash. The plugin developers say it's installed properly and we have to get the info from NMI that goes in there but it seems like NMI has provided complete info for connectivity. Just that the [login to view URL] plugins do not take the proper info. We can't make something up that is not there.