Custom Registrar Module - Unable to renew domains

[stef]

I have created a domain registrar module for Network Solutions but when I try to process a domain renewal request via the manage orders page the checkbox to 'Send to registrar' is always disabled so the request never gets sent to them. I have written the RenewDomain function so it's not and have tried setting the expiry date to a reasonable value but with no success. Anyone know why this field is disabled and how to make it available?

 

Thanks a lot for any insight.