I have the exact same problem with a Moxi/Motorola DVR and the Sony RM-AV3000. They (the boxes) use an infrared wireless technology called eXtensible Multimedia Protocol (XMP), formerly called Two-Way Infrared Protocol (TWIRP), which is also used by Dreambox and Escient devices. This technology uses multiple infrared pulses with 16 burst pairs with 16 different burst combinations.

The Sony remotes can either send, only one command at a time, or multiple commands with a single push of the button. In either case, it makes the remote interface very slow or impossible to use. Some users have reported better results by briefly pressing the buttons or varying the amount of "press time" during the “learning process”. But this is very time consuming and completely a "trial and error" process at best, and I never got all keys to work satisfactory.

The Harmony 880, 688, 676, and URC-300, MX-700, URC-9910 all have been reported to support the XMP protocol. But this means incurring the expense of new remotes, and for me (with three AV 3000) it has never been an option.

Sorry I don't have better news for you but I wanted to let you know that you are not alone, and also to expand on DT's post of "It must be a code format that the VL710 simply doesn't like" as very few remotes do like it...Maybe the RM-AV4000 will change all that, but its of no help here and now.

If anyone has found a solution or an useable work-around for XMP and Sony remotes, would love to hear from yea.