I cannot find a way to make a beamed group of notes of the same voice, where the first note of the group has stem down and the other have stem up. (Or the opposite). Like in image below.
I tried the suggestion to use [force the beam to be centered] as mentioned here (Multiple stem direction on beamed note), although the result is messy.
In Finale this used to be a very easy task.
Thanks
Did you force the beam to centered or did you just drag the beam manually? There’s a specific operation for centering beams - if you didn’t use it, reset the beam then center it.
Edit: just trying it out, I can see that the centered beaming is interesting given the pitches in this specific example! I suspect that the issue is several notes that in your example are stem-down should technically be stem-up based on their staff position, and you can’t simultaneously force the stem direction and force a centered beam. If you raise the pitches of the stem-down notes so that the last note is a B, it looks nice & behaves better (which I appreciate, is not how composition works).
Thank you Lillie_Harris!
Yes you are right. Transposing upwards by steps of intervals of a second, the problem remains, until you reach a point that the last note is a B. Also, transposing down (from the original) the problem remains until a point that the last note is a D, where the command “force centered beams” does nothing at all. 
Anyway, I hope the team will fix it.
These short scales are from Bach’s Chaconne (I am writing a guitar transcription to learn Dorico). In Finale it was easily written as seen below:
In a future version of Dorico it will be possible to force Dorico to create a centred beam with any combination of pitches, regardless of how their natural stem directions are calculated, so it will be easily possible to achieve this notation.
Thank you Daniel!
And congratulations for your excellent work! 
Kostas
