Your nightmare is about to end! (I hope :-)
There are a couple tag settings that must be filled out in order for this tag to work:
1. Type - this should be set to 'roitrack.cgi' for this pixel (see your example pixel above).
2. Ad ID - this value is also available in your example pixel as "aid". This also needs to be set.
Your understanding of the mapping is correct. You can map a Tealium variable to 'pname000', 'pvalue000', etc. This will work fine if you are only mapping the order_total and order_id variables. If ValueClick is expecting a list of product data then I think you will need some more advanced extensions. You can contact your Account Manager to get further support for this.
One thing to note: it looks like ValueClick is expecting a list of "name" and "value" paired parameters. Without seeing a ValueClick integration guide, I can't be sure, but they might be expecting something like this:
pname000 = 'order_id'
pvalue000 = '29.95'
If you can get clarification about this from ValueClick we can be sure we send the correct values.
Remember to "Accept as Solution" when your question has been answered and to give kudos to helpful replies.