Well, I\'ve got my Developer Certificate linked with it\'s private key. Works Fine.
I\'ve downloaded my iOS Profile of distributor, but it says Valid signing identit
For Developer certificate, you need to create a developer .mobileprovision profile and install add it to your XCode. In case you want to distribute the app using an adhoc distribution profile you will require AdHoc Distribution certificate and private key installed in your keychain.
If you have not created the cert, here are steps to create it. Incase it has already been created by someone in your team, ask him to share the cert and private key. If that someone is no longer in your team then you can revoke the cert from developer account and create new.