Since the controller is not sending a proper trigger, but just a message whenever it moves, you can't use any of the normal trigger-related Capytalk messages.
The evaluation of a Capytalk expression is triggered whenever any of the values in the expression is received. This means that you could use an EventVariable to accumulate the value each time the message is received by the Paca(rana):
| sum value signedValue |
sum := EventVariable new.
value := (!cc06 * 127) rounded.
signedValue := (value gt: 63) true: 128 - value false: value).
sum <~ (sum + signedValue)
This expression cannot be used with any other Capytalk that might also trigger the evaluation (for example, another Event Value or a time-dependent Capytalk message) because then expression evaluation could be triggered by something other than !cc06, causing the value to be accumulated even though the !cc06 message was not sent.
This will work best if you use a SoundToGlobalController to send the accumulated value to your other Sounds.