How to add other soundchanges in a score?

Hello everyone,
I wonder if anybody stumbled upon that particular issue before.
My goal here is to add at least another soundchange for strings in a score. By default, strings only have 3 possible soundchanges - arco, pizzicato,and tremolo - which can be triggered by adding a simple staff text.
And I'd like to add "Detache" to that list because I am using the Squidfont Orchestra soundfont,which provides 4 separates instruments for strings, "legato" , "Detache","pizzicato" and "tremolo", and I wanna be able to use each one of them on the fly.
Since I don't want to add anoter staff in my score, I'd like to know if it is possible to add a 4th soundchange in the mixer.
I already tried to edit the "instruments.xml" file, but logically, nothing changes in the UI. Is there any way to do that?
Thanks for taking the time to read and for trying to help!
Mac