Hi Cvetan,

If you want to setup your Internet connection over GPRS and/or 3G , the automatic configuration from your provider will not work. You need to setup them manually!

You can do that going to: Applications / Settings / Internet connections / Connections , make sure that Cellular data is selected then press Edit, then you can put the setting there:

You can use fallowing example, but keep in mind that I'm not in Bulgaria so I can not check if these settings actually work.

Connection name: Vivacom
Connection type: GPRS - leave that, you can change it later from /Settings / Network mode/ Dual - you can follow Zlatko post.
Click on NEXT button...
Access point name: internet.vivatel.bg
username: vivatel
password: vivatel
Click on Finish and you are done!

These are for MMS massges, but for the internet you do need them:
MMSC http://mmsc.vivatel.bg
MMS proxy 192.168.123.123
MMS port 8080
MMC 284
MNC 03

These are APN settings for other Bulgarian providers, if you need them at some point.

M-Tel
Name Mtel
APN inet-gprs.mtel.bg

MMSC http://mmsc/
MMS proxy 010.150.000.033
MMS port 8080
MMC 284
MNC 01

GLOBUL
Name Globul
APN globul
Username globul

MMSC http://mmsc1.mms.globul.bg:8002
MMS proxy 192.168.087.011:8002
MMS port 8004
MMC 284
MNC 05

Greetings Martin,