I have Studio One 3.
1. I don't know about Beatstep or if it can be used as a MIDI controller for synths at all. Can it? If it can, then
2. Does MIDI learn work when you for example use an Arturia application in standalone mode?
(And are the parameters you wan't to assign a control avaible for normal MIDI learn?)
The knobs are all mapped and recognized in S1 as well.
3. Does this mean that you have mapped the Beatstep device setup you use for Studio Ones Control Link that's Studio ones form for MIDI learn? If so, then normal MIDI learn does'nt work in the DAW, when using that device setup.
Studio Ones Control Link make more things possible. It can be used no matter you have a controller mapped for it or not and it's easy to use. The mapping expand the functionality.
4. Have you tried to assign your controls using Studio Ones Control Link?
I don't know if this helps. But it might. I can only suggest you look into it. As i don't know about Beatstep, then i can't do more.