Edit: Ok, I don't know what happened, but I actually saved the .pem file to the device first this time before opening the certificate manager (instead of opening the certificate manager directly from the browser) and it seems to have imported it and it works to connect to Exchange. Apparently if you open the cert manager from the browser (by navigating to a .pem file) it doesn't import it correct (even though the cert is listed in certificate manager). So now things are cool. Thanks!