Create a self signed certificate that will act as a certificate authority.
Install this certificate on the iOS device (easiest way for me to do this was to host the certificate on a server and visit the link in safari and then download it). The iOS device will now trust any a server with a certificate that has been signed by this certificate authority
Create a new certificate that is signed by the certificate authority you created in step 1.
Use this newly signed certificate on your Worklight server