I am trying to achieve using some ableton effects on a VST in my host application (Studio One). I assume this is not possible therefore I am wondering if ableton has the option of using external VST plugins while in slave mode?
It seems you can't use the vst plugins in live while in slave mode. I tried Live lite 8 with Studio one and only the native plugins of Live are available. It says "Unfortunately, plug-ins are deactivated when running Live as a ReWire slave".
By the way, it is the same for "Reaper" as Re-wire slave, so it seems the way Re-wire works!
Rewire only works one way afaik: MIDI into the slave app, audio out from it. And yeah no VST's in the slave app. Reaper has a set of drivers called ReaRoute however that can pipe audio into a rewire slave, if you ever want to try that. It feels a little inelegant to me and it may introduce a little latency. Having puzzled over this kind of thing myself, I've gotten used to just bouncing things back and forth between DAWs, i.e. render your track, process in Ableton, render, finish in S1.