You can't any of the built-in remotes as Sling have decided to send 3 copies of every IR signal each time you tap a button and your receiver is a bit sensitive. Here is a Custom Remote that ahs the repeat rate set to zero.
Any use ?
ADB 2800.zip 1.7 K
I'm sorry, but it didn't work, but that is my fault.
I have some more information that I failed to provide and correctly.
I was using the generic ADB2800 remote that slingbox provides on its dropdown list which is giving me the double signals, along with the other ADB boxes. My actual cable box is the ADB-2721W.
I still tried the file you attached and I got nothing, no imputs when pressing the keys. The files were installed correctly but the signal didn't match the ADB-2721W.