Finally OTR in Kadu is usable. After fixing one bug that was a result of my misunderstanding of LibOTR API we can finally start and stop OTR conversations from Kadu and accept incoming OTR sessions.
This does not mean that Kadu supports 100% of OTR protocol. Multiple sessions for one account are not supported (and won't be for 1.0 release), generating keys is still synchronous (this will be changed soon) and there is no way to verify peer identity (this will be fixed for 1.0 release).
All of the code is now in master branch on gitorious and github - please download it and test ;)