On portable (as opposed to in-my-study) machines, I have Thunderbird set up with different profiles; one accesses mail through the in-house mailserver (lots of filtering and additional security); the other picks up and sends the mail using direct connections to the relevant servers. Accessing the profile manager is, in the usual way of things, a matter of inputing a command line parameter "-profilemanager" using start -> run.
There seems to be no way to do this in the U3 version of Thunderbird. It does not seem to me likely that simply copying profiles from, e. g., the Thunderbird installation on one of my notebooks would be trivial.
What am I missing? Or, is this a case where I would do better to just forget about U3 and revert ot a portable but not U3 version of the software?