This was my test, it seemed OK. I specified both volume and velocity.
!NoteWorthyComposer(2.751)
|Editor|ActiveStaff:1|CaretIndex:2|CaretPos:0
|SongInfo|Title:""|Author:"<Name>"|Lyricist:""|Copyright1:"Copyright © 2021 <Name>"|Copyright2:"All Rights Reserved"
|PgSetup|StaffSize:16|Zoom:5|TitlePage:Y|JustifyVertically:Y|PrintSystemSepMark:N|ExtendLastSystem:N|DurationPadding:Y|PageNumbers:0|StaffLabels:None|BarNumbers:None|StartingBar:1
|Font|Style:StaffItalic|Typeface:"Times New Roman"|Size:10|Bold:Y|Italic:Y|CharSet:0
|Font|Style:StaffBold|Typeface:"Times New Roman"|Size:8|Bold:Y|Italic:N|CharSet:0
|Font|Style:StaffLyric|Typeface:"Times New Roman"|Size:7.2|Bold:N|Italic:N|CharSet:0
|Font|Style:PageTitleText|Typeface:"Times New Roman"|Size:24|Bold:Y|Italic:N|CharSet:0
|Font|Style:PageText|Typeface:"Times New Roman"|Size:12|Bold:N|Italic:N|CharSet:0
|Font|Style:PageSmallText|Typeface:"Times New Roman"|Size:8|Bold:N|Italic:N|CharSet:0
|Font|Style:User1|Typeface:"Times New Roman"|Size:8|Bold:N|Italic:N|CharSet:0
|Font|Style:User2|Typeface:"Times New Roman"|Size:8|Bold:N|Italic:N|CharSet:0
|Font|Style:User3|Typeface:"Times New Roman"|Size:8|Bold:N|Italic:N|CharSet:0
|Font|Style:User4|Typeface:"Times New Roman"|Size:8|Bold:N|Italic:N|CharSet:0
|Font|Style:User5|Typeface:"Times New Roman"|Size:8|Bold:N|Italic:N|CharSet:0
|Font|Style:User6|Typeface:"Times New Roman"|Size:8|Bold:N|Italic:N|CharSet:0
|PgMargins|Left:1.27|Top:1.27|Right:1.27|Bottom:1.27|Mirror:N
|AddStaff|Name:"Staff"|Group:"Standard"
|StaffProperties|EndingBar:Section Close|Visible:Y|BoundaryTop:12|BoundaryBottom:12|Lines:5|Color:Default
|StaffProperties|Muted:N|Volume:127|StereoPan:64|Device:0|Channel:1
|StaffInstrument|Name:"Violin"|Patch:40|Trans:0|DynVel:10,30,45,60,75,92,108,127
|Clef|Type:Treble
|Key|Signature:F#,C#|Tonic:D
|TimeSig|Signature:4/4
|Dynamic|Style:ppp|Opts:Velocity=127,Volume=10|Pos:-8
|Note|Dur:Whole|Pos:1^|Opts:Crescendo
|Bar
|Note|Dur:Whole|Pos:1^|Opts:Crescendo
|Bar
|Note|Dur:Whole|Pos:1^|Opts:Crescendo
|Bar
|Note|Dur:Whole|Pos:1^|Opts:Crescendo
|Bar
|Dynamic|Style:fff|Opts:Velocity=127,Volume=127|Pos:-8
|Note|Dur:Whole|Pos:1
|AddStaff|Name:"Staff-1"|Group:"Standard"
|StaffProperties|EndingBar:Section Close|Visible:Y|BoundaryTop:10|BoundaryBottom:10|Lines:5|Color:Default
|StaffProperties|Muted:N|Volume:127|StereoPan:64|Device:0|Channel:2
|StaffInstrument|Name:"Viola"|Patch:41|Trans:0|DynVel:10,30,45,60,75,92,108,127
|Clef|Type:Treble
|Key|Signature:F#,C#|Tonic:D
|TimeSig|Signature:4/4
|Dynamic|Style:fff|Opts:Velocity=127,Volume=127|Pos:-8
|Note|Dur:Whole|Pos:1^|Opts:Diminuendo
|Bar
|Note|Dur:Whole|Pos:1^|Opts:Diminuendo
|Bar
|Note|Dur:Whole|Pos:1^|Opts:Diminuendo
|Bar
|Note|Dur:Whole|Pos:1^|Opts:Diminuendo
|Bar
|Dynamic|Style:ppp|Opts:Velocity=127,Volume=10|Pos:-8
|Note|Dur:Whole|Pos:1
!NoteWorthyComposer-End
Edited: This doesn't work with percussion, only on instruments requiring a moving bow or stream of air.