Not showing payment methods

Hi, i’m using gravity forms and pronamic iDeal to manage payment from charity website, and i’m using mollie iDeal to receive the payment.

I just want to create a simple form with some fields and text input to insert how much people will give their money for charity, what i want to achieve is when people click submit charity, they’re redirected to mollie payment page.

I don’t know how to do this actually, and i’m trying to using issuer dropdown, but when i’m using issuer drop down, it doesn’t show any payment method, from backend and frontend, here is the screenshot :
http://i59.tinypic.com/f1a59j.png
i’ve already disabled the no conflict settings on gravity forms, i’ve read an similiar issue about this, and you suggest to remove the issuer dropdown, it’s bit unclear, what should i use?

https://wordpress.org/plugins/pronamic-ideal/