From my experience you need to replace like for like with either a current or older hw/sw number.
I might be wrong about that however as I didn't actually confirm that myself - just researched via various forums.
I found a replacement DSP amp for my goosed one with a HW/SW number that was one revision older than mine and it works perfect.
EDIT: actually I'm lying - I don't have the DSP effects available - only the EQ. but tbh I don't think I'm missing much as the effects are crap anyway.
So I think that could corroborate the fact that you need matching HW/SW numbers to get things working without any other coding tomfoolery.
Post your end result up so others can benefit perhaps?