python_stubs directory placed in wrong location (PyCharm 3.1)

Hi all!

The current Win7 environment has the user home set to a network drive (U:).
Because of that PyCharm startup is taking a long time. Therefore I changed idea.properties to these values (Z: is a local drive):

idea.config.path=z:/.config/.PyCharm30/config
idea.system.path=z:/.config/.PyCharm30/system

All is working fine and startup is much faster now.
But a background process is rebuilding the skeleton files (which takes a long time) and is placing them here:

u:\.PyCharm30\system\python_stubs\-946255732\

It seems that this skeleton process doesn't follow the settings in idea.properties.

Or is there any other setting I have to make?

Thank you very much for your help and your great tool!

Best regards,
Marcel