Currently, I am developing an App using the AppConKit 3. In the debug perspective of the IDE, there is a view at the bottom called "Device Log". It is supposed to display log messages generated by the mobile device. There are two fields to input an URL and a port and a "Connect" button. I'm not sure which settings to use, the default settings 127.0.0.1 with port 4012 did not work for me - I couldn't see any log messages.
To enable the log view, you have to enable the log server in your app's server part. Switch to the Java perspective, unfold the "WebContent" area and also the "WEB-INF". In there, you should find the ibiz.prop file. In that file, uncomment the two lines
#the port the remote device connects to
devicelogport = 4000
#the port the remote UI connects to
guilogport = 4012
When you now restart your app (server), you should be able to connect to the device log server and see log messages.