Microsoft has just updated KB 2870742:
FIX: An Alternate Content Provider does not work in a task sequence for a System Center 2012 Configuration Manager SP1 site
Consider the following scenario:
- You configure an application that takes advantage of the Alternate Content Provider (ACP) to distribute packages in a Microsoft System Center 2012 Configuration Manager Service Pack 1 (SP1) site.
- You create a task sequence that includes an “Install Application” step.
- You include a single application in the step.
- You specify the following options, and then you deploy the task sequence:
- Download all content locally before starting task sequence
- When no local distribution point is available, use a remote distribution point
- Allow clients to use a fallback source location for content
- A client receives the policy for deployment, and then begins to process the task sequence according to schedule. Or, you click Install for the task sequence deployment in Software Center on the client.
In this scenario, the ACP is not invoked in the ContentTransferManger.log file when you download the content.