Please forgive the cross-post, but I think this probably belongs in this forum rather than in 'Tips, Techniques & Tutorials', which is where I originally posted because I found a related thread there. This is also an updated version of that post...
The thread on this last November (in 'Tips, Techniques & Tutorials') doesn't seem to me to have answered the question - at least not for my situation. I'm using GPO in Digital Performer 4.61, and I have the current version, 18.104.22.168 (with seemingly varying numbers of 0s before the 3). For what it's worth, my Mac is a dual 2.3 GHz G5 running OS X 10.4.7.
I cannot, whatever I try, make Vibraphone KS sustain, either by holding the key down or by using the sustain pedal. No matter what I do I just get a short 'dink' from every note. I've looked at the text file in the library - no clues there. According to GPOUpdate.pdf, "Sustain pedal=standard sustain"... but not for me it doesn't.
Since my original post, I've found how to download the '9. Notation' folder mentioned in last November's thread, and lo and behold! The vibraphone (non-KS) in there behaves as it should. But all the ones in Dry, Wet Audition and X-Custom suffer from this same problem.