Kasatome

Such a tease. . .

If you are running tekkit 1.2.5, then you have the wrong PermissionsEx file. The one you have is for 1.4.2. http://dev.bukkit.org/server-mods/permissionsex/files/ I'm using the one for CB 1.2.5-R4.0. Try removing the PEX file you have and replacing it with that one.

OK, This may not be the most helpful post ever, but I hope to steer you in a good direction. Where as I use Showcase standalone, I can verify that it works, but I use Precious Stones for protecting things. Which leads be to believe that World Guard may either have an incompatibility, or there may be a setting or permission somewhere. I'd check to see if SCS is compatible with WG, if so, then check your permissions.

The logblock thing you said sparked in my head. I am using logblock and I noticed it doesn't record block placement. However it does for some blocks. "Kasatome created x136" those are the redpower slabs, covers etc. I don't have a clue if this is helpful/new info, but I wanted to let you guys know that I found those to be recorded.