Since Set-up says you bring your target into a more vulnerable position, being prone is a more vulnerable position, and both Set-up and Attack to Knockdown don't cause damage, would you think it would be possible to combine the two in one action? I'm inclined to say yes, but what are your opinions?

Hrm, browsing through martial arts maneuvers some more, Sweep is of course the next step in line.

Could you, say, Attack to Knockdown, as a Set-up, while benefitting from sweep, so cause knockdown, do normal melee damage, AND get net hits added to the next attack, as well as the possible +3 for the target still being prone on your next attack?

The first step would just be making Set-up somewhat useful. The last is turning powerful indeed though.

You mean like getting two different effects from 2 different MA Maneuvers in one Action....?
I don't thinks thats Rai ....it shure isn't Raw

with two Dances in one
Medicineman

Indeed: you definitely can't combine them. You can set them up and then knock them down.

Actually:

Emphases mine, of course.
Set-up is a menuver, Attack to Knockdown a combat option. RAW seems to support those two being used together at least.

Ah, I misunderstood. Following Medicineman, I thought we were talking about 2 maneuvers in the same action (not Action Phase). Those crazy characters with their two-hand defense painful disarm riposte nonsense…

I do feel like Set Up shouldn't be allowed on top of just anything. It's a vague maneuver that (worst case) could be applied to everything you do. I agree that the specific case of Knockdown makes sense if anything does, but it's also something-for-nothing. Basically, you're sacrificing the same thing twice (normal attack damage), and that's not kosher. Finishing Move works because you're sacrificing something different (an interrupt action), but if you stacked Setup+Sweep/KD+Disorient… bleh.

I'm fine with Setup being useful, somehow - its kind of lame, as is.

This was my line of thinking as well. I would probably say that if the Attack to Knockdown fails to actually cause knockdown, you wouldn't get your Set-Up bonus on your next attack either (failure for the attack to be succesful, which is Set-Up's requirement), thus making it a bit more risky than just using Set-Up alone. Either way, I just stumbled across the idea paging through Arsenal. Thought it might be just that little boost that Set-Up needs to make it useful, rather than the resounding 'meh' that's usually uttered in relation to it, like Udoshi just did.

Since I'll be actually playing a campaign again for the first time in ages, I might actually ask my GM if she agrees, and see how it works.

I changed my Mind
I think its quite OK to combine one or more MA Maneuvers with combat Options
After all its still "only" Melee

with a Melee Dance
Medicineman