Question Buildcraft with Modifyworld (Cauldron)

This question is about mod-plugin compatibility but I couldn't find a better place to ask. Cauldron support is down and Buildcraft forums are empty.

I have an issue with Buildcraft on my Cauldron server. Since Quarries and similar stuff may become a perfect griefing instrument I want to limit their usage to non-protected areas only. I know this can be done because a lot of servers actually have Buildcraft installed but they have no griefing problems with it. I googled the problem and they say the best solution is to use Modifyworld from PermissionsEx and give Buildcraft ([buildcraft]) all permissions.
However, when I got to business and tried doing the above I realized Modifyworld blocks all BC/IC activity no matter what permissions I give to them. I tried giving [buildcraft] OP but nothing changed.

My questions are:

1. Is there any way to debug Modifyworld (1.7.9) in order to see who fails in block placement/destruction (something like "12:34:43: xxx tried to place block but was denied in permissions")? If I knew who fails I could give perms to that fake player.
2. What is the mechanism Buildcraft or/and IndustrialCraft use to work with Bukkit, if any? Do they try to communicate with some spiecific plugins or do they use Bukkit event system?
3. What is the most common solution to this problem anyways? How do they limit BC on those big servers with mods so it doesn't touch protected areas?

Thanks in advance

 

@OLEGSHA, this is a really bad place to be asking questions about Cauldron. Most of us have no idea how to use it. Lol.