I also think you wouldn't be particularly wrong if you said *chevmeH tlhoy'* instead of *chevwI' tlhoy',* for example. It would be like the difference between /border wall/ and /wall of the border:/ one is said and the other isn't, but the other is still perfectly understandable.

But on the other hand, {pe'wI' taj} sounds strange, doesn't it?

Only because I know the phrase pe'meH taj. A pe'wI' taj is obviously a cutter's knife, the knife of someone who cuts.

-- 
SuStel
http://trimboli.name