Grrr, I am getting crazy with all my audio problems !
be patient, it's worth the wait :) .
Loading snd_usb_audio is enough. If it's present, the UA-25 will work.
I run jack (via qjackctl of course) with the following parameters:
/usr/local/bin/jackd -R -P83 -p64 -dalsa -dhw:2 -r48000 -p256 -n3
The only thing you need to adjust is -d, maybe -dhw:1.
BTW: alsaconf cannot configure your USB devices.
IF you try the following and it doesn't work, please send the output of:
cat /proc/asound/cards
uname -a
cat /proc/asound/version
The audio section of /etc/modules.conf
Best regards
ce