I have had hit and miss with pin availability on the nokia data cables, but every sony erricsson one I have bought off deal extreme has had something that works for reset available on it, on the underside of the board on an unlabled pin.
I found it as described with probing and opening and closing the port to trigger it changing.
IMO the FTDI cables are better, they have a serial number in them so that you dont have the comport number change in windows depening on how things are enumerated. If you will only ever have the one device connected to the PC then the prolific ones may work for you, but I have several and I have to change things depending on when and where I plug it in on windows.