Im running 10.4.10. Have an no name usb-db9 thats detected on the latest knoppix as a PL2303 and works. Shows up on my mac as:
Bus Power (mA): 500
Speed: Up to 12 Mb/sec
Product ID: 0x2008
Vendor ID: 0x2478
I can't get it to work with your driver, the driver from prolific or anything else I tried. Have modified Info.plist with PID & VID and deleted extension cache files before loading the module. It is never recognized as anything but a generic device and no new tty devices show up. Please help.
You should add more debug information about the matching process. I have added the product/vendor ID to the plist, so it should be work in the next release.