Skype Portable - multiple instances

With the standard version of Skype, you can run multiple instances by adding /secondary to the command line.

It would be useful to be able to run Skype Portable as a second instance of the Skype client (ie on a machine where Skype client is already running).

Is it possible to put something in a SkypePortable.ini file to enable this - as one can, for instance, with Thunderbird and some other applications?

Regards

Nick