You need to download and install the following package :
http://am4computers.com/downloads/Hauwei/Linux_Hauwei_Movistar3G.zip
The Movistar 3.5G will be installed on your system. It will be invoked as soon as you plug your USB modem. You need to create a profile for Mobinil from Options, Profile Management, New and set the APN to mobinilweb.
And don’t forget to change the type of connection to Modem, not NDIS.
You can also use UMTSmon, which is a tool to control and monitor a wireless mobile network card (GPRS, EDGE, WCDMA, UMTS, HSDPA) in a laptop running the Linux operating system. It handles PIN codes, operator choice (roaming), signal strength and network statistics, sending/receiving SMS . You can grab the latest version from http://umtsmon.sourceforge.net/.