ApplePieXpto

It's challenging. You could also store NBT data to an entity on the forge mod event, and then read the NBT on the bukkit event, as forge events have priority over bukkit events. You could also remove the NBT data later when not needed on forge side, maybe calling a forge mod method from the plugin side? Still haven't tested that yet.

Importing the plugin classes and trying to instantiate their methods will call a class not found exception (also tried with reflection and same problem), haven't tried the other-way around though. (On a Thermos server -> fork of KCauldron -> for of Cauldron -> fork of MCPC+).