Running into frustration: Title.displayFormat

[Alhifi]

Hello,

i'm still using my Roku Soundbridges with the minimserver, everything works fine.
Until today I defined the Title.displayFormat as follows:

Title.displayFormat={$title^$subtitle^(^)}

I use the subtitle tag/field to store information like "12'' Version", which also VirtualDJ did, so the result is

Name Of The Title (12'' Version)

Now I want the following string for Title

Name Of The Title (12'' Version) (xx/yy)

where xx should be the tracknumber of the title and yy should be a value like Totaltracks of the album.
Actually I only have the tracknumber within the music-file, not a total tracknumber, so maybe it must be calculated or something else.
I have "subtitle,track" defined as "itimTags" in the minimserver properties, but everything I tried, nothing is working, tests with only the value of "track" didn't work. Could someone please help me finding the right format string to get this working?

Bye
Alhifi