Where do we do the <add Key

and would it look like this??

add key="MobilePhoneUserAgents" value="iphone,ipod,ipad,android,iemobile" />

You can also configure which devices will use the mobile skin from configuration settings. It is based on a comma separated string of fragments of a user agent, so if a user agent string contains the fragment it will be detected as a mobile device. The default value is configured like this:

add key="MobilePhoneUserAgents" value="iphone,ipod,android,iemobile" />

So if you know of a fragment unique to another device you want to try and use it with you could add it to this string, or you could add ipad if you wanted to.