I am working with Virtuemart 2. I have an authorize.net credit card payment method created in Virtuemart under payment methods and set to groups Anonymous and Default. However, when I goto check out and click on "Select Payment Method". There is no payment method to select at all. I am stumped. I have had to go into the code in virtuemart a lot to fix several issues. I am not sure if it is something simple in the back end, it WAS showing at one time, but seems to have disappeared. Any help would be GREATLY appreciated! Thank you.
Please check you have enabled the authorize.net payment plugin under joomla plugins . if it has been enabled it will be listed under payment method and also make sure you have published the payment method ;)
A littlebit late, but this was the solution to the similar problem I had.
Be sure to choose the right shopper groups for the plugin, including "anonymous" if you want to allow guest checkout.