Cisco phones with Dell switches

I've got a Powerconnect 5524P that I'm playing with and trying to get to work with Cisco phones.

From what I've found, the Dell switches do not speak CDP, so they cannot use it to identify the Cisco phones and put them on the right VLAN.   I found that I could set up the OUI table to make it identify the phones, and I used it to get one phone working.

The problem is that I checked all the phones at this client and they have over 30 different OUIs on the phones.   The Dell switch would only let me enter 15 in the table.   How do I get around this?   Surely there is a better way to identify the phones then checking their MAC addresses!

Thanks,

- Marc