Maybe I have been out of the SMP Mods for too long, thought they went right into the Server.jar itself? If there's more steps I wouldn't know how exactly that would work as I only use Bukkit anymore. If you Email (or wait til morning and use live chat) the MCProHosting support they could answer any questions about whether it will work. Less ya mail em at midnight they usually respond in under an hour. 
I've been tempted to use SMP mods, but never got into it, so I'm not too much help really. But being that they have had jars up that are SMP Mods, I'd assume it's possible.
Never used a bukkit server, or been on one, only thing I know is smp mods, pain for people ot get on cause they have to have every single one installed to get on, but its worth it, the smp mods are much more in depth then what plugins can do currently, but from what I hear with Bukkit joining Mojang the future of mods is bound to be plugins only.
with the jar, when you install modloader if mkes a new folder called mods, you drag a zip'd mod (if told to do so) and put it in mods folder and it runs the mod automatically, its easier cause all you have to do is swap out zip files when stuff updates