Retrieving and setting split window settings for plugin development

I am currently working on a plugin called "Tab Session" which is quite useful if you want to save and load certain sets of open tabs. It works well, but an important feature is still missing: Splitted Tabs are ignored and are lost when reloading a session.

I asked the specific question on Stackoverflow, but got no attention:

http://stackoverflow.com/questions/19728469/retrieving-and-setting-split-window-settings-for-intellij-idea-plugin-developmen

Maybe someone can help me with this. I find it quite diffictult to find the right methods without a documentation.