I have a SE T610 too... but I have to compose *99***1#
The "1" is to tell to the phone to use the number one (gprs in my case) profile for connecting to internet.
If you use more than one profile (like me... I have wap gprs, wap cmd, internet gprs and so on...) simply change the "1" with the correct profile number... ie: *99***5# (if your internet profile is the number 5)
It works very well!!
bye!