udev and the option umts 3G card

How i hate to debug udev - i did it a couple of times and everytime i hate do to it again. I wanted udev to create a modem symlink in case i plug in my 3G Option UMTS Card. The problem is the Card has an OHCI USB Host Controller presenting 3 usb-serial devices. Only the first one can be used to connect - Ignoring the fact that all three run through udev create a random symlink on any device whatever comes first. Here is how i solved this:

SYSFS{idVendor}=="0af0", SYSFS{idProduct}=="6000", PHYSDEVPATH=":1.0/ttyUSB", SYMLINK+="modem"

the PHYSDEVPATH makes shure i am only attaching the modem symlink to the device :1.0 on the new OHCI bus. As i also match
vendor and product of the Option card this will only create a symlink on the first port of the option card.