RSA encryption method on IOS using kSecPaddingOAEP

I need a method that will encrypt a string (over 128 bytes, so chunked) with a public RSA key. I have had a stab at it myself, but to no avail as you can see from this link: [login to view URL] I have got as far as converting the key to a PEM license, and I can run teh encrypt without error, but when trying to decrypt it, it fails with "Error occured while decoding OAEP padding" The deliverable will be a method which will take a string to be encrypted and a string containing the PEM certificate and will return a valid encrypted string which I can verify with the private key. IOS 6 compatible please.