IRDA port not found on 2490 [HP iPAQ hx2490 Pocket PC - 126053]

I am developing an application to read a data logger using the IR port of a HP iPAQ hx2490b. I have several versions working on Dell and earlier HP devices but the 2490 just won''t read the IR. Doesn''t even get to see the port. Is there anything peculiar about how the IR is set uo and used in the 2490? This isn''t specific to an individual device, I have several units on test, all doing the same.