looks like the link to yousendit has expired.
For beeper volume you can use: config.maxBeeperVolumeLevel = 4;
Duration can be set via: config.beeperDuration = 2000;
Frequency: config.beeperFrequency = 2900;
I am sure you have seen the programmer's guide but if not its here: (https://atgsupportcentral.motorolasolutions.com/content/emb/docs/manuals/17099102a.pdf)
but the documentation is not up to date...
Still the same for the PTT method, no documentation can be found..