I don't think this would work.
The WBP's IR link is designed to emulate a hardwired keyboard and mouse. That's why the keyboard is recognized in w/out an OS. This also indicates that the resulting signal is being handled by the motherboard as PS/2 input. This is definitely the case for conventional wireless keyboards. When you install a Logitech wireless device, it's installed as a regular mouse/keyboard, not as an IR device. In addition the Palm IR-sync software is handled from within an OS over a recognized IR port.
However this is conjecture since I just got my WBP and have yet to install an OS. Maybe if this motherboard integrates IR, it handles things differently and you reassigned to COM port?!? Anybody with a Windows install should be able to check out the device manager and see if an IR device is detected...