Mike
A couple of possibilities exist (that I can think of).
The cable you are using may not actually be wired correctly thus no signal detected. I cannot advise what cable you should use, other than to contact the manufacturer and see if other cables exist for that model UPS.
David Pennycuick spoke of making his own cable in these forums recently, do a search on his name as Author.
The UPS you have may not signal all of the various states that powstatd can detect. Again you would need to contact the manufacturer to ascertain this.
I would start with the cable, it may be as simple as one of the pins is not connected that in fact needs to be.
Regards
Ray Mitchell