Setting up IIS 7.5 for AD Client Certificates for iOS devices

Go to IIS manager, select your server, select authentication, ensure Active Directory Client Certificate Authentication is enabled.

Then go to your website, select SSL settings, select require SSL, and select "Require" under Client Certificates.

That should be all if you've already set everything up in AD (which you seem to have, according to your question).

I would put this as a commment, but I dont have enough reputation D:

First you need an asp.net website with certificate authentication, you don't need to worry about the iPad part at this point, just get the website running on localhost, most of the configuration is done on the web.config(at least it is for a web service, my experience with certificate authentication is only in WCF, but I assume asp.net should be the same way).

After that I would try to connect to the site with different browsers using different certificates, to check if everything works correctly.

And finally after it's working on your desktop you should try your site on the iPad. With this part I have no idea how it works exactly(i don't own any iDevices), but if it's like a desktop browser, you should be able to choose the certificate when you try to access the website.

Let me know if this made any sense to you lol