HI,
I have more than 6 years experience in wordpress.
I have developed some payment plugins for GravityForms, I can show you demo url if you want.
I have integrated NAB payment into some ecommerce site, I can show demo url if you want.
My plugin is wordpress plugin, easy to install and config in wordpress admin.
I can start working and finishing this payment plugin very soon.
I have checked your additional info, can you explain how to validate customer info in ' Salesforce accounnts'? is there any information about this?
Thanks