Here's an updated version of the PayMeNow processing script for Virtuemart. Our client needed to use this gateway, and the included script wasn't working for us.
This version is a modified version of Soeren's authorize.net processing script.
I didn't include the fsockopen method, since we only require curl, but it should be fairly simple to extend.
http://www.mediafire.com/?dzhtntdy9zu (http://www.mediafire.com/?dzhtntdy9zu)