iPhone ad hoc distribution with team agents certificate

I'm struggling with a problem that's very similar to this StackOverflow issue: iPhone ad hoc distribution as a team admin with team agent's certificate?. Unfortunately, the answer provided there didn't quite work for me.

Here's the overview:

I'm working on a new project for a 3rd party company that has already shipped one iPhone app. I've set myself up as a Team Admin under their account, generated a development certificate for myself, and been able to develop the new app successfully. I can install and test on my iPhone without a problem.

Now it's time to create an Ad Hoc build for the client to test. This is where I'm struggling.

They already have a distribution certificate. To generate my Ad Hoc provisioning profile, I need to tie it to that existing certificate. Unfortunately, that certificate is not on my machine, so the Ad Hoc profile isn't working.

I've had the client send me the .p12 and .pem files from their keychain, and added them to my login Keychain. What else do I need to do?

I've tried downloading the distribution certificate and dragging it on to Xcode -- no effect. I don't see it under my list of Developer Profiles in the Xcode Organiz开发者_运维问答er.

I've tried to import it into Keychain Access. No effect. It doesn't seem to appear anywhere.

What am I missing???

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Since I never got any response to this question, I'll answer it myself.

Or rather, I'll refer to the answer rob5408 provided to this question: iPhone: Can a dev other than team agent build an app for distribution

That did the trick.