I think it is first necessary to show them examples of success by making the sale by TripleClicks. Explain that they will have new customers around the world, so that they will increase their turnover and sales area. Explain that having their merchandise TripleCilcks is already advertising articles, and thus a gain for their trade. I think there is anyone in the world who does not want to increase its business.
I hope this advice will help you convince ECAs.