Ok, here's what I found by googling.
First of all, I didn't realize that there are actually two devices: /
dev/cu.usbserial and /dev/ttyusbserial; both are apparently loaded.
Secondlly, there are commands for loading and unloading kernel
extentions but my results with them have been not totally successful;
you must run them from root. They are kkextload and kextunload plus
the path. Again, use with caution.
Thirdly, one link I found also gave directions for editing a plist;
since safari doesn't copy from safari urls (grrrrrr!) I'm including
the url here. Not sure how to do this as I don't know how to edit a
plist; also the newest version of the driver, which is now 1.2.1r2,
may not need this. But I'd like to get a look at it and see if the id
numbers match those in my system profiler.
http://www.osxhax.com/archives/000006.html
--
Cheryl
"Where your treasure is,
there will your heart be also".