How Do I add BT Synergy 2110 handset to NTL VS2000 base station?

I am trying to add a BT Synergy 2110 handset to an NTL VS2000 base station, but the 2110 will not find the base station, even if I set the base station to * (according to manual is connect to strongest signal). VS2000 already has 2 NTL handsets connected that work fine.