GoDaddy issued certificates are not trusted by the Sony P1i phone and so if you are using a GoDaddy issued digital certificate for ActiveSync on one of these phones you will be prompted to accept the certificate at each sync. As this kills the purpose of push email sync you will want to stop the prompt.
You do this by installing the GoDaddy trusted root certificate. On any Windows computer that works when connecting to a website protected with your GoDaddy certificate run mmc.exe and add the Certificates snap-in, selecting the local user option. Browse to Trusted Root Certification Authorities and click on the Certificates node. Find and right-click the Go Daddy Class 2 Certification Authority and choose All Tasks > Export. Export the certificate as a DER encoded binary X.509 (.CER) file to a folder on that computer.
Email that file to the owner of the Sony P1i and sync the phone to download their email (confirming the prompt that we want to remove). Open the email and download the attachment. Once the attachment is downloaded (which might involve syncing again and confirming the certificate prompt) open the attachment. The phone will install the certificate into its certificate store. No more prompts!