How to transfer user data and settings from install Skype to Portable Skype?

OK, I use the install version of Skype on my PC, but would like to exchange it for the portable version. I can open the setup file and create a new virgin version of Portable Skype on a USB stick which I could copy to my PC. But how do I get my settings and contact lists of my Skype accounts into the portable version? Please help!!!