Converting Jailbreak certificates to PEM

This is how you can use OpenSSL to convert signed, PKCS12 stored, certificates exported from Jailbreak to PEM (Base64 encoded DER format):

openssl x509 -in CA_certificate.cer -inform der -outform pem -out CA_certificate.pem

openssl pkcs12 -in YOUR_personal.pfx -out YOUR_personal.pem