Default Qtek 8020 As USB Modem

I want to use my smartphone as GPRS modem via IrDA. But I don't know how I can install my smartphone as modem on my Windows 98.

As alternative - USB GPRS modem. But I can't install driver USBMDM.INF (from CD with smartphone).

Please, help!

Windows 98
Qtek 8020 (1.1.31.22)