Anyone using a Polar monitor with a none Polar USB IrDA interface?

The other day I decied to bite the bullet and shell out for a Polar S720
plus an extra speed kit to my road bike (my LBS made me a offer I could
not refuse that included a RaceFace seat post and a RaceFace carbon
handle bar - pretty sweet!).

But so far I'm not to impressed with the whole thing. I had problems
fitting the sensor and wheel magnet on my roadbike with it's flat carbon
fork and flat carbon spokes (It's a Giant TCR-TEAM with Mike Burrows
carbon blade spoke wheels), theese details was solved by my LBS
supplying an none Polar magnet and a little creative use of rubber on my
part. Why Polar doesn't supply something that fits with carbon forks out
the box I don't get and carbon spokes aren't that rare either.

However there is a much worse problem since I can't bring the S720 to
interface with my PC, I'm guessing it could be because I have a none
Polar USB+IrDA adapter and I could just shell out the extra cash and get
the real one but I'd rather not due to having enough cables on my desk
allready (USB to camera, USB to MP3, USB to mouse).

When trying to connect in the PPP program it just gives me a "Uable to
find COM port" or something along thoose lines even though it's
configured to use USB:-(

PC configuration:

WinXP Pro (With all the latest patches)
PPP program latest version 4.00.023
Longshine USB-IrDA Adapter (LCS-8141)
(http://www.longshine.de/pdf/8141.pdf)

All help appriciated.

Kind regards

Bruno