Has anybody had any success with udev?

I need to use oss and have tried to create a udev.rule to connect two
identical usb midi interfaces and identify them by the usb port.

I ended up creating the devices in /dev/ and /dev/snd/ and named them
/dev/midi1, /dev/midi2 and/or /dev/snd/midiC1D0, /dev/snd/C2D0.

They show up correctly in the folder /dev/ but I don't know how to assign
them to anything alsa-base.conf can use.

The first one that gets plugged in is always midi1 no matter where I plug it
in. If I plug only one of them into the second usb port it will create midi1
and midi2. alsa-base.conf cannot seem to use the udev rules.
It looks like something is assigning the soundcard numbers before or after
udev.

Any ideas?

Ingo