Setting up push syncing with a Debian mirror

Hi all,
I am currently running a Debian (Wheezy) server which is hosted in a professional datacenter. The datacenter is located in Germany, and is directly connected to major backbones. As I do have loads of unused bandwidth and disk space, I’d like to contribute to Debian’s infrastructure by hosting and maintaining an Aptitude mirror.
I’ve already set this up using the ftpsync scripts, and manual syncing already appears to work. However, I’d like to be able to utilize push syncing, however this requires an upstream mirror to connect to my server via SSH and issue a certain command. Is there any way of setting this up with an upstream mirror? The Debian Wiki page on the topic goes to great lengths in explaining how push syncing works technically, but is rather vague on how to arrange push syncing with an upstream mirror…
If anyone could shed some light on this issue, I’d greatly appreciate that!
Many thanks!
Robin

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