Congratulations on your HPM-100s. Those replacement tweeters should work fine in there, from what I see of their specs. It's important, of course, that the drivers work well with the crossovers, especially with a system as complex (five drivers!) as this one.
I've had HPM-100s around for a few years. I think they're pretty decent, butnot everyone agrees. They do tend to polarize people's opinions; one of those things that most people seem to either love or hate. I used mine for my television speakers for a good while, and they did a great job at making movie sounds "involving." They're decent at music, too, although it can be a little hard to get them to produce a real "soundstage." Mine are in storage at the moment, but will soon come out again to appear "in rotation>"
Again, congratulations!