I talked to Tim Ring and he said they have not written software for the LM-2S that can handle the Heavy Steam ULT. They may get it done, but he is also not sure if it will fit on the LM-2S. He has said that before with other software updates and ULT sounds, but they were able to get them all to work fine on the LM-2S. Back when they first released the major sound update with all the new features, it was originally designed only for the LM-3S (which was relatively new at the time). Most Railpro guys still had a ton of LM-2S's so I pressed him to try and get the code to work on the LM-2S. He did, and all the new features and ULT sounds work just fine on those modules.
My guess is that he will do the same for the Heavy Steam ULT and LM-2S. The file size for the ULT apparently isn't as large as other files. So it would just be a matter of updating the LM-2S from 2.09 to 2.30, which is quite a jump.
-Kevin