Tremolo problem

see attached

I assume the issue is that you want the notes with hollow heads but beamed. That's not really "normal" - it's kind of non-standard, but it's not necessarily all that uncommon, either. It isn't clear from your example how many beats you want it to take up (which might be why some reject this notation), but if you can get it to appear with the beams the way you want (eg, enter two sixteenths, then add the teeomolo, which will produce the appearance of two eighths), you can hollow out the notes head using the note properties menu (right click).

Here is how I have done it in the past.
Experiment with different durations for the rests to get the appearance you want.

1] Enter a quarter-beat rest
2] Enter a 32nd-beat note
3] Enter six consecutive 32nd-beat rests
4] Enter another 32nd-beat note (an octave lower than the first, in this case)
5] [Shift]-click from the first note to the second note
6] Go to the Beam Properties palette and double-click on the "Middle of Beam" symbol
7] [Ctrl]-click each of the rests in turn
8] right-click and make the rests invisible
9] [Ctrl]-click on each of the two notes
10] Go to Note Properties and make the note heads into minims

If you also want to hear it on playback then:
11] Enter a series of 32nd notes in the Second Voice
12] Make them invisible
13] From Note Properties, set velocity type to User and velocity to 0.

If you intend on having the tremolo marks on the stems, select the markings with the stem included. I do not know if this is what you meant, but I hope it is useful.

https://musescore.org/en/node/14903