Installing usb_modeswitch to connect usb gsm modems on CentOs

I have a  huweai e1732 modem which i want to use as simple smsgateway for my personal use and outgoing voice trunk for asterisk .

As soon as I connect it to usb ,linux detects it as external storage and never shows as ttyUSB in /dev list .

To make it work as serial modem i had to install usb_modeswitch

[root@sriba usb_modeswitch.d]# yum install usb_modeswitch
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
* base:
* epel:
* extras:
* updates:
Setting up Install Process
No package usb_modeswitch available.

This package is in rpm forge

import the dpg key

rpm --import

verify the package download
rpm -K rpmforge-release-0.5.2-2.el6.rf.*.rpm

Instaleld the package
rpm -i rpmforge-release-0.5.2-2.el6.rf.*.rpm