Configure interaction whitelist correctly at worldguard?

I host a small Minecraft server with mods and plugins (KCauldron), on which I also installed Worldguard.

Our trading system is based on gold nuggets as currency, and to set up stalls, I'd like to use the Exchange O-Mat from IndustrialCraft2.

Unfortunately, this does not work in the otherwise protected marketplace with the flag use = allow. And somehow I'm too stupid to add that in the interaction whitelist.

The id is IC2: blockPersonal 1 or 535 1 (with metadata 1).

but as I also try or enter, either, Worldguard aborts and does not work, it gives as error message "… Could not be found", or there's no error message, but the block can't be used in protected areas anyway.

Since the research was unfortunately not particularly effective, I ask now here, if someone can help me there?

I also like to use another block from another mod, as long as it does not require too complicated technology around it and is compatible with a gold nugget based trading system.

Jap, my minecraft version is 1.7.10, that KCauldron and pretty much everything is outdated, does not bother me next, almost everything great at the new updates can be retrofitted and the mod variety is in 1.7.10 just gigantic.
The solution was in the case of another mod (trading booth), which secures the box of the seller automatically without Plugin against other players.