Problem with automated recurring contributions and "pay later"

Recurring contribution + pay later combination is not supported.

In 4.1 a form rule in Main.php ensured that the end-user did not pick this combination:

"You cannot set up a recurring contribution if you are not paying online by credit card."

However when the Pay Later UI was changed and integrated with payment processor radio selection, this form rule was "lost".

Please re-implement the form rule.

— original post ----
I created a CiviContribute page with both automated recurring contributions and "Pay Later".

I then tried the page as a donor would, I choose $50 as the amount, automated recurring for once a month for 12 installments. I also choose "Pay Later".

A number of problems occurred:
1) CiviCRM created a recurring subscription record and a contribution in the status of Pending, but the field "civicrm_contribution_recur.processor_id" is null.

2) As a result of 1, the "Cancel" feature for the recurring subscription that is located on the "Contribution" tab fails with an ugly error message from Authorize.net:
Payment Processor Error message
E00003: The 'AnetApi/xml/v1/schema/AnetApiSchema.xsd:subscriptionId' element is invalid - The value '' is invalid according to its datatype 'AnetApi/xml/v1/schema/AnetApiSchema.xsd:numericString' - The Pattern constraint failed.

3) As a result of number 1, there is no way to remove, or post check payments, or allow a credit card to be added to the subscription.

4) The confirmation/thank you page/email receipt all include language telling the donor that their donation will be processed automatically once a month.

I am running version 4.2 alpha 3