Yearly recurrence with Moneris payment processor causes error

When you configure recurring contributions and allow the user to choose a yearly recurrence unit, the contribution page displays an error and the contribution does not go through. The error is:

Payment Processor Error message
null: ** ERROR ** - unable to register recurring transaction!

I believe this is due to the fact that Moneris does not support a recurrence unit of 'year'. You would need to send a recurrence unit of month, with period unit of 12 to achieve a yearly recurrence.

I'll provide a patch for this, and will also look through SVN to see if this has been fixed in a later version. For my case, an upgrade of Civi is beyond scope.