One of the first hurdles was the fact that the Panasonic x700 is not listed as a supportable device in Panther. This was easily overcome by a published hack
The only thing to note when making changes to the file example is to use correct the device address. You can also change the phone name as well. I changed mine to the same name as what I named and paired the mobile as.
If you do not know the name or device address, goto: System Preferences > Bluetooth > Devices
Next was the really curious bit. I attempted to add my 6600 back as another sync device and it started complaining. So it seems that 1.5 can only manage one symbian phone sync at a time.
The solution, remove and add. The painful part in that is the x700 is not supported.
Unix script to the rescue. Create 2 files, one for each phone, e.g.
Script version: swap_phone.sh
cd /Library/Application\ Support/SyncService/501
cp SymbianConduitDefaults.plist_$1 SymbianConduitDefaults.plist
Finder version (its not in a hidden directory):
Your HD > Library > Application Support > SyncService > (your user id, i.e. the only folder you have access to) 501
Same thing, create 2 files and just rename or replace using [apple]-c and [apple]-v when needed
Apple isync support can be found a here.