Since there are no official drivers available for Windows 7, you need to install the modem manually. Please proceed and install the available drivers. The setup package is not configure to install the drivers automatically in Windows 7 and you will need to use Device Manager to update the files.
Install the drivers and software then restart the computer. Go to Device manager, right click the modem's entry and use Update Driver. Point the installation window to the folder in Program Files and manually select the INF file. Windows will then install the files and the rest of the features automatically and then you can use the modem accordingly.