Following my previous post - I have figured out a work around solution to get IVM to acknowledge and use the Netcomm modem.
If i use my VOIP settings (voip phone number/pwd) it works, seems to have problems with detecting Netcomm modems on an analogue line (PSTN)
To avoid further windows/driver/modem frustrations I will use the VOIP for IVM answered calls and PSTN analogue phone line for incoming faxes (using Win fax on PC)
For all those out there with Netcomm modems, let me know if you do get them to work using the old analogue PSTN lines.