Some updates to the problem: i've installed VL SOHO 5.8 RC3, i've done again the scripts, and now when i try to connect i get this error "/dev/ttyUSB0 unknown option". I can't remember the exact message, but it sounds like that. It reffers to a part in a script from /etc/ppp/peers/, the umts script. The /dev/ttyUSB0 is the first option that appears in that script, indicating which device to use. I've changed it to look like a comment, the pppd call umts nodetach command works, but there's no connection! And I really hate the way the terminals are acting on this new version of VL. They show the output of the pppd command in only one line.
Both LEDs are blinking, after the connection only one should blink, and that would be the sign that I am connected.
Now i am really sorry that I've changed my OS.The result of this: quitting Vector Linux in favor of Windows XP.