This is accomplished by creating a type of trunk link between the switch and phone, allowing the link to pass traffic for both voice and data. Then you create vlan interfaces on the switch that correspond to the subinterfaces.
Configure the port that connects IP phone to switch as follows:
# switchport mode access
# switchport access vlan vlan-id
# switchport voice vlan vlan-id
IP phone should obtain IP from dhcp pool of the voice subnet and register with BE3K. The PC should obtain IP from DHCP on data subnet.
Thanks
Sanjay