twin bt studio 1100?

hi,

i had a bt studio 1100 twin the handset to base 1 got droped and cracked this is the base with phone and power the second base just has power. i brought a replacement base and handset but am unable to either register the handset to my original base or the twin to the new base i have tried to follow the instruction book but it dosnt seem to cover this. i wondered if anyone might know how to get two phones working again?