CiviCRM-generated reciepts for automatic Authorize.net transactions

[SarahG (FountainTribe)]

When some uses the back-office area of CiviCRM to set up an automated credit card contribution ( in my case using Authorize.net) CiviCRM will email a receipt to the donor as soon as it gets an update from Authorize.net that a scheduled payment was processed.

The receipt emailed out looks like:
---------------------------------------------------------------------------
Please print this confirmation for your records.
Contribution Information

Amount    $ 0.18
Date    October 7th, 2011 12:13 PM
Transaction #    390234518540

This is a recurring contribution. To modify or cancel future contributions please contact us at info@someorganization.org.
------------------------------------------------------------------------------

How can I do the following:
a) Customize the message so it includes more information, logo, etc?  I checked the system settings at: http://www.someorganization.org/civicrm/admin/messageTemplates?reset=1   but did not see anything related to this message.

b) Prevent the messages from going out entirely.

[TwoMice]

Hi Sarah,

That looks an awful lot like templates/CRM/Contribute/Form/Contribution/ThankYou.tpl

Not sure how to prevent it from going out, though.

- Allen