Mio S501 GPS

I just bought a LAK-17a (LOVE it, BTW) and I bought a used Mio S501 on the
net.

I have all the instructions for unlocking the Mio but can't get it to work.
The instructions begin with connecting the Mio to the PC as a mobile device.
I have a desktop running XP and Active Sync and a laptop running Vista and
Windows Mobile Device Center. Neither of these will connect to the Mio.

I can connect my Compaq 1550 to the XP machine via Active Sync but not to
the laptop using a USB to serial converter.

The unlock instructions would have me execute programs on the Mio through
the PC to get everything set up but, since I can't figure out how to connect
it (reading all the instructions over and over), I'm at a loss.

Currently, I can get a desktop on the Mio and, using File Manager, can start
LK8000 or XCSoar but neither of them will connect to the GPS function on the
Mio.

Any help out there?

Dan