I deal with ad agencies. Funny story, I just fired two of them. Told one to take a flying leap, not putting up with their crap anymore no matter how good the money was. Two days later, another ad agency called and took up the ad space that just freed up. Then the first ad agency grovelled, so I agreed to take their money from them again. True story, sometimes I am just too nice. The second one then decided my terms weren't acceptable (though it's what we'd agreed to) so I asked for a premium to change - which I could justify. They said no, I said sorry, let's stay in touch because I do want to work this out. They thought about it, decided it was good for their clients, and came back and negotiated. So despite my best efforts to rid myself of taking their money, they've managed to persist and overcome.
Anyway - I have the same problem. No idea how to crack this market head on. I do have something I do that gets their attention but it's not as direct as I'd like.
One person who is a contractor in the business was kind enough to tell me that generally I want to speak to the 'new media' person. That'll get me to the right department.
Unfortunately, when I start talking about the innovative services I offer, I draw blank stares from them. They like to talk about social media and SEO, but when I put it together in a package like nobody else has, they've no idea what I'm talking about.
I take consolation in that while I don't have a clue what these people are about, they're probably looking at these new internet punks showing up in their turf, and thinking the same thing about me.