Check your 2wire firmware, if it is V5, then it can be used as a router, but if it is V6, Singnet firmware has disabled WAN router connection function and it cannot be used on Starhub line as a router, it only can act as a wireless Ap point ( to connect Starhub cable to the 2701HGV-E's LAN.
There is another chance for this 2700HGV-E modem as a router with V6 firmware to used on Starhub connection, you may flash it with other firmware and try, but do it at your own risk.
There is Qwest firmware to download. the URL is:
2Wire 270X Firmware Update for Windows and Macintosh
Please note, there is no Singtel V6 firmware to download, so after do that you cannot revert back to Singtel firmware.
regards.