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
"Valid Signing identity not found" This is because you don't have the private key for distribution certificate.
If the distribution certificate was created originally on a different Mac you may need to import this private key from that Mac. This private key is not available to download from your provisioning portal.
When you import the correct private key to your mac , XCode's organizer will recognize your already downloaded distribution profile as a "Valid profile"
However if you do not have access to the original Mac which created those profiles, the only option you have is revoking profiles.
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.