Lute tablature stems

[JonathanS]

Hi
I am trying to use lute tablature in Sibelius Ultimate.
the note lengths are showing as stems - that's as I'd expect - but the stem that it shows for a minim / half note is exactly the same as the one it shows for a crotchet / quarter note, which makes it very hard for a lutenist to make sense of. Crotch3ets should have a single tail (like those for a quaver/eighth note) in conventional notation)
Here is what I am getting:

Sibelius tablature example.jpg (56.23 KiB) Viewed 3115 times

It ought to be something like this (ignore difference in pitch & time signature change):

Tablature as it should be.jpg (47.42 KiB) Viewed 3115 times

I have tried all the stem types under notation/noteheads and the different tab options but none of those do what I want.
Is there any way to achieve what I need? Any ideas greatly appreciated...