When a gatekeeper claims to be the decision maker but you know he is not, how do you work around him to the reach the person who can truly say yes to the sale?

If you stop to think about it for a minute, every single one of the various contacts you have in a prospect or account is both a buying influence and a decision maker. The Gatekeeper Technical Buying Influences are making decisions about how well your proposal meets specs and how well it will work on the job. But only one of them has the decision-making power to give you the sale.