After lot of coding, I can say that this phone is fully supported. All basic services should work in my Gammu branch and changes should be soon merged to official branch.
So what works?
If you're using original Sony-Ericsson cable, try following configuration, and send me gammulog, if anything goes wrong:
[gammu]
connection = at
port = /dev/ttyACM0
logfile = gammulog
logformat = textall
Branch links are available at http://cihar.com/gammu/, you can directly download from http://dl.cihar.com/gammu/snapshot/.
Update: All needed changes had been merged in 1.09.00 release, so you don't have to care about development versions.