The LS25 is controlled using RF, so no ordinary IR remote is going to be able to work it. However, there is a box called the C-1024 which you can use to convert IR signals into something the LS will understand (but it's expensive: $219).
You can buy it from here: [Link: audioauthority.com]
If you do decide to get that box, you'll need a remote to work it as it doesn't come with one (surprising considering the price, but there you go). I can program the codes into a "One For All" brand remote control if you like. I can also program in the codes for your LS35 while I'm at it.