该证书由未知的权威机构签署

I need to create ipa file for testing purposes. I go to Keychian access -> Certificate assistant -> Request a certificate from a certificate authority and create some.certSigningRequest file. Then I upload that file to customer iOS Provisioning Portal and create development and distribution certificate which I download and install on my vmware mac. When I select certificate i got message: I need to create ipa file for testing purposes.