I would have thought the OP would have got something by now.
Coming at this from a UK perspective, isn't it rather cheeky of PCCW to actually charge separately to have home Wifi enabled (the NETVIGATOR Home Wireless Service) in their Netvigator ADSL modems?
No it's not cheeky. It's very deliberate to confuse and gauge customers.
If they complain, tough luck, there is no customer protection in HK
I did email PCCW about using my own router and they said:
"Thank you for emailing NETVIGATOR.
With regards to your message, it is with regret to inform you that
technical support on third-party equipments, i.e., router, and its
step-by-step settings are unavailable from us. We do not impose any
restrictions on the use of wireless routers. However, we hope that the
following information could be of help to your situation.
In general, to connect to your NETVIGATOR broadband service, you just
need to configure your router settings and select DHCP. Usually,
advanced settings are not necessary. Otherwise, we would recommend you
to contact your wireless router vendor for more information."
There is no problem at all in using your own router with PCCW