have found the solution. just for the record.
i have to use the snapshot variation (rightclicking) on each trigger pad to let the keyswitches function so that each triggerpad contains a different plex phrase. thus select a triggerpad, select a variation, take the snapshot
if i do this for each triggerpad (and each variation has a different plexphrase) i got the result.
the question remains though if someone knows how to assign different plexphrases to midi-notes so i can use them as keyswitches without the workaround of the triggerbuttons… that would be even better