Hi,
Igonre my previous post.
You can assign VLAN 2 on the SF 302 switches as the voice vlan. VoIP enabled devices are then associated with the voice vlan once recognized as such by the switch (by Telephone OUI, or CDP/LLDP-MED advertisements). You can also manually set the port to VLAN2, but this is useful only if you don't need voice and data on the same port.
If the 302 doesn't recognise the IP phones as VoIP devices, try updating the OUI in the switch database (pg. 198 of the 300 series switch manual). This should ensure that the Cisco switch correctly tags traffic from the phone's MAC as belonging to the Voice VLAN and allow the phone to download it's configuration details.
Regards,
T.